Systems and methods for achieving a pre-determined factor associated with an edge region within a plasma chamber by synchronizing main and edge rf generators

ABSTRACT

Systems and methods for achieving a pre-determined factor associated with the edge region within the plasma chamber is described. One of the methods includes providing an RF signal to a main electrode within the plasma chamber. The RF signal is generated based on a frequency of operation of a first RF generator. The method further includes providing another RF signal to an edge electrode within the plasma chamber. The other RF signal is generated based on the frequency of operation of the first RF generator. The method includes receiving a first measurement of a variable, receiving a second measurement of the variable, and modifying a phase of the other RF signal based on the first measurement and the second measurement. The method includes changing a magnitude of a variable associated with a second RF generator to achieve the pre-determined factor.

CLAIM OF PRIORITY

The present patent application claims priority, under 35 U.S.C. §119(e),to U.S. Provisional Patent Application No. 62/366,567, filed on Jul. 25,2016, and titled “SYSTEMS AND METHODS FOR ACHIEVING A PRE-DETERMINEDFACTOR ASSOCIATED WITH AN EDGE REGION WITHIN A PLASMA CHAMBER BYSYNCHRONIZING MAIN AND EDGE RF GENERATORS”, which is incorporated byreference herein in its entirety.

FIELD

The present embodiments relate to systems and methods for achieving apre-determined factor associated with an edge region within a plasmachamber by synchronizing main and edge radio frequency (RF) generators.

BACKGROUND

Plasma systems are used to control plasma processes. A plasma systemincludes multiple radio frequency (RF) sources, an impedance match, anda plasma reactor. A workpiece is placed inside the plasma chamber andplasma is generated within the plasma chamber to process the workpiece.

It is important that the workpiece be processed in a similar or uniformmanner. To process the workpiece in a similar or uniform manner, variousparameters associated with the plasma reactor are controlled. As anexample, it is important to control directionality of ion flux duringprocessing of the workpiece. The control in directionality helpsincrease an etch rate and achieve a certain aspect ratio of features ofthe workpiece.

With the processing of the workpiece in the uniform manner, it isimportant to simultaneously maintain lifetime of various components ofthe plasma chamber. With an application of RF power to some of thecomponents, the components wear faster and do not last for theirlifetime. Moreover, due to such wear, the components adversely affectthe directionality of ion flux, which adversely affects the uniformityin processing of the workpiece.

Moreover, current dielectric etch tools have fixed edge hardware. Forexample, a height of a lower electrode extension of the plasma reactor,or a material of the lower electrode extension, or a gap between anupper electrode and a lower electrode are optimized to process theworkpiece at its edges. The fixed edge hardware does not allowflexibility in processing the workpiece at its edges.

It is in this context that embodiments described in the presentdisclosure arise.

SUMMARY

Embodiments of the disclosure provide apparatus, methods and computerprograms for controlling directionality of ions in an edge region of aplasma chamber by using an electrode within a coupling ring and forachieving a pre-determined factor associated with an edge region withina plasma chamber by synchronizing main and edge radio frequency (RF)generators. It should be appreciated that the present embodiments can beimplemented in numerous ways, e.g., a process, an apparatus, a system, apiece of hardware, or a method on a computer-readable medium. Severalembodiments are described below.

It is difficult to meet process specifications at the edge of a waferdue to a tradeoff between a profile angle or tilt at which the wafer isetched and an etch rate. The etch rate depends upon ion flux at the edgeof the wafer and chemistry, e.g., mixture, types, etc., of one or moreprocess gases used to process the wafer. The ion flux at the edgereaching the wafer is a function of ion flux that enters the plasmasheath and the shape of the plasma sheath at the edge. The ion focusingeffect is a function of a difference in wafer plasma sheath thicknessabove the wafer and edge ring plasma sheath thickness above the edgering that controls the plasma sheath beyond the edge of the wafer. It isimportant to maintain a uniform plasma density beyond the edge of thewafer and minimize the difference between the wafer plasma sheath andthe edge ring plasma sheath to improve the etch rate and to maintain aprofile angle to be about 90 degrees, e.g., between 89.5 degrees and90.5 degrees, between 89 degrees and 91 degrees, etc. Also, it isdesirable to control wear of the edge ring so that the edge ring is usedfor its lifetime, e.g., greater than 500 hours, etc.

In some embodiments, a knob for independent control of plasma parametersassociated with the edge ring is provided. The knob is provided byembedding a powered electrode in a coupling ring, and providing RF powerto the electrode or by coupling the electrode via a variable impedanceRF filter to ground. The providing of the RF power is sometimes referredto as providing active power to the electrode and the coupling of theelectrode via the variable impedance to ground is sometimes referred toas providing passive power to the electrode. There is no optimization inupper electrode step location, edge ring height and shape, edge ringcoupling materials, etc., to control the plasma parameters. However, insome embodiments, the upper electrode step location, the edge ringheight and shape, and/or the edge ring materials are controlled inaddition to the active or passive power provided to the electrode tocontrol the plasma parameters.

In various embodiments, a capacitively coupled RF powered edge ring isdescribed for improving performance at the edge of the wafer. By varyingan amount of the active or passive power coupled to the edge ring,plasma density of the plasma at the edge region, sheath uniformity ofthe plasma at the edge region, etch rate uniformity of the plasma at theedge region, and tilt at which the wafer is etched in the edge regionare controlled. There is no provision of RF or direct current (DC) powerdirectly to the edge ring. The capacitive coupling of power to the edgering reduces, e.g., eliminates, etc., chances of any arcing between thematerials of the edge ring and RF feed parts used to deliver powerdirectly to the edge ring.

In some embodiments, a system for controlling directionality of ion fluxat the edge region within a plasma chamber is described. The systemincludes an RF generator that is configured to generate an RF signal, animpedance matching circuit coupled to the RF generator for receiving theRF signal to generate a modified RF signal, and the plasma chamber. Theplasma chamber includes the edge ring and the coupling ring locatedbelow the edge ring and coupled to the impedance matching circuit toreceive the modified RF signal. The coupling ring includes the electrodethat generates a capacitance between the electrode and the edge ring tocontrol the directionality of the ion flux upon receiving the modifiedRF signal.

In various embodiments, a system for controlling directionality of ionflux at the edge region within a plasma chamber is described. The systemincludes a first RF filter that is configured to output a first filteredRF signal, a second RF filter coupled to the first RF filter forreceiving the first filtered RF signal to output a second filtered RFsignal, and a plasma chamber. The plasma chamber includes the edge ringand the coupling ring located below the edge ring and coupled to thesecond RF filter. The coupling ring includes the electrode configured toreceive the second filtered RF signal to further generate a capacitancebetween the electrode and the edge ring to control the directionality ofthe ion flux upon receiving the second filtered RF signal.

In some embodiments, a system for controlling directionality of ion fluxat the edge region within a plasma chamber is described. The systemincludes an RF filter that is configured to output a filtered RF signaland a plasma chamber. The plasma chamber includes the edge ring, and thecoupling ring located below the edge ring and coupled to the RF filterto receive the filtered RF signal. The coupling ring includes theelectrode that generates a capacitance between the electrode and theedge ring to control the directionality of the ion flux upon receivingthe filtered RF signal.

In some embodiments, a control scheme for tunable edge plasma sheath(TES) is provided. Plasma sheaths above the wafer and wafer edge aredriven by separate RF generators, e.g., a master RF generator and aslave RF generator, etc. A magnitude of each sheath voltage and phaseangle between wafer and edge RF sheaths are monitored by voltagepickups, e.g., voltage sensors, etc., and the magnitude is adjusted toachieve process results, e.g., one or more factors, etc., at the waferedge.

In some embodiments, a control of RF plasma sheath at the wafer edge isdescribed. RF power is independently applied to the wafer and thecapacitively coupled edge ring by two generators, e.g., the master RFgenerator and the slave RF generator, etc., of the same RF frequency. RFvoltages and phases are measured at outputs of main and edge ring RFmatches and fed to the slave generator. Then frequencies of both thegenerators are adjusted to the same value and locked. Thereafter, phaseangle between two voltage waveforms of the RF voltages is adjusted andlocked. And finally, slave voltage output value is set to a specificvalue that corresponds to process results at the wafer edge. Byadjusting phase locked edge RF plasma sheath, a pre-determinedperformance, for example, 0 degree edge tilt, a pre-determined degreeedge tilt, etc., is achieved at the wafer edge. In several embodiments,the frequencies are adjusted after adjusting the phase angle between thetwo voltage waveforms. In some embodiments, the RF voltages and phasesare measured after the frequencies are adjusted.

In various embodiments, a slave RF generator locks frequency with amaster RF generator. Then, the slave RF generator is turned on, e.g.,provides power, operates, supplies an RF signal, etc. Thereafter,automated phase and voltage control are achieved based on pre-definedsettings.

In some embodiments, a slave RF generator executes frequency locking andphase and voltage control for each state, e.g., state S1 and S2, etc.

In some embodiments, a method for achieving a pre-determined factorassociated with the edge region within the plasma chamber is described.The method includes providing an RF signal via a first impedancematching circuit to a main electrode within the plasma chamber. The RFsignal is generated based on a frequency of operation of a first RFgenerator. The method further includes providing another RF signal via asecond impedance matching circuit to an edge electrode within the plasmachamber. The other RF signal is generated based on the frequency ofoperation of the first RF generator. The method includes receiving afirst measurement of a variable associated with an output of the firstimpedance matching circuit, receiving a second measurement of thevariable associated with an output of the second impedance matchingcircuit, and modifying a phase of the other RF signal based on the firstmeasurement and the second measurement. The method includes changing amagnitude of a variable associated with a second RF generator to achievethe pre-determined factor.

In various embodiments, a system for achieving a pre-determined factorassociated with the edge region is described. The system includes aplasma chamber having a main electrode and an edge electrode, a firstimpedance matching circuit coupled to the main electrode, a secondimpedance matching circuit coupled to the edge electrode, and a first RFgenerator coupled to the first impedance matching circuit to provide anRF signal via the first impedance matching circuit to the mainelectrode. The RF signal is generated based on a frequency of operationof the first RF generator. The system includes a second RF generatorcoupled to the second impedance matching circuit to provide another RFsignal via the second impedance matching circuit to the edge electrode.The other RF signal is generated based on the frequency of operation ofthe first RF generator. The second RF generator receives a firstmeasurement of a variable associated with an output of the firstimpedance matching circuit. The second RF generator receives a secondmeasurement of the variable associated with an output of the secondimpedance matching circuit. The second RF generator modifies a phase ofthe other RF signal based on the first measurement and the secondmeasurement. The second RF generator changes a magnitude of a variableassociated with the second RF generator to achieve the pre-determinedfactor.

In several embodiments, a non-transitory computer readable mediumcontaining program instructions for achieving a pre-determined factorassociated with the edge region within the plasma chamber, whereinexecution of the program instructions by one or more processors of acomputer system causes the one or more processors to carry out aplurality of operations is described. The operations include providingan RF signal via a first impedance matching circuit to a main electrodewithin the plasma chamber. The RF signal is generated based on afrequency of operation of a first RF generator. The operations furtherinclude providing another RF signal via a second impedance matchingcircuit to an edge electrode within the plasma chamber. The other RFsignal is generated based on the frequency of operation of the first RFgenerator. The operations include receiving a first measurement of avariable associated with an output of the first impedance matchingcircuit, receiving a second measurement of the variable associated withan output of the second impedance matching circuit, and modifying aphase of the other RF signal based on the first measurement and thesecond measurement. The operations include changing a magnitude of avariable associated with a second RF generator to achieve thepre-determined factor.

Some advantages of the herein described systems and embodiments includeachieving the approximately 90 degree profile angle. An amount of theactive or passive power supplied to the electrode within the couplingring that is coupled to the edge ring is changed to achieve the 90degree profile angle. Ion flux is measured and the ion flux iscontrolled based on the measurement. The ion flux is controlled bycontrolling an active power source or a passive power source that iscoupled to the electrode within the coupling ring to change acapacitance between the electrode and the edge ring. The capacitance ischanged to achieve the approximately 90 degree profile angle. Thecapacitance is used to control a voltage of the edge ring to furthercontrol the etch rate of etching the wafer at the edge region. Thevoltage of the edge ring is proportional to an impedance of the edgering compared to ground. The profile angle helps achieve an edgeprofile, e.g., a top CD, a bow CD, etc., uniformity that is less than apre-determined amount, e.g., less than 3%, less than 2%, less than 4%,etc.

Moreover, other advantages of the herein described systems and methodsinclude extension of the edge ring lifetime by varying edge ringvoltage. Once the edge ring is worn, e.g., has reduced height, etc., theplasma sheath is bent and ion flux becomes focused on the wafer edge. Asa result, edge tilt becomes out of a range defined in a specification.Adjusting the edge ring voltage leads to more uniform plasma sheath andputs wafer edge process parameters back into the range defined in thespecification. By implementing the electrode within the coupling ringinstead of the edge ring, lifetime of the edge ring is increased.

Further advantages of the herein described systems and methods includethat RF voltage on the edge ring is independently controlled by theslave RF generator that operates at a similar, e.g., same, etc., RFfrequency as the master RF generator that applies power to the wafer,and in phase with main RF power supplied by the master RF generator toavoid any distortion of etch pattern at the edge of the wafer. Suchin-phase application of the RF voltage with the similar RF frequencyfacilitates achievement of a factor, e.g., tilt, etc., at the edge ofthe wafer and simultaneously does not affect, e.g., has a minimal effecton, etc., a plasma sheath at a center region of the plasma chamber.

Other aspects will become apparent from the following detaileddescription, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments are understood by reference to the following descriptiontaken in conjunction with the accompanying drawings.

FIG. 1 a diagram of an embodiment of a plasma system to illustratecontrolling directionality of ions in an edge region of a plasma chamberby using a coupling ring.

FIG. 2A is a diagram of an embodiment of a system to illustrate couplingof an electrode within the coupling ring to an impedance matchingcircuit (IMC) via a radio frequency (RF) filter and providing activepower to the electrode.

FIG. 2B is a diagram of an embodiment of a system to illustrateproviding passive power to the electrode embedded within the couplingring.

FIG. 3A is a diagram of an embodiment of a system to illustrate use ofion flux to tune power supplied by an x megahertz (MHz) RF generator oran x1 kilohertz (kHz) RF generator to control impedance of plasma withinthe edge region to further control directionality of an ion flux in theedge region.

FIG. 3B is a diagram of an embodiment of a system to illustrate use ofion flux to tune an RF filter to control the impedance within the edgeregion to further control directionality of the ion flux within the edgeregion.

FIG. 3C is a diagram of an embodiment of a system to illustrate use ofdirect current (DC) bias to tune power supplied by the x MHz RFgenerator or the x1 kHz RF generator to control the impedance of theplasma within the edge region to further control directionality of theion flux in the edge region.

FIG. 3D is a diagram of an embodiment of a system to illustrate use ofthe DC bias to tune the RF filter to control the impedance of the plasmawithin the edge region to further control directionality of the ion fluxin the edge region.

FIG. 4A is a diagram of an embodiment of a mesh electrode, which is anexample of the electrode embedded within the coupling ring.

FIG. 4B is a diagram of an embodiment of a ring shaped electrode, whichis another example of the electrode.

FIG. 5 is a diagram of an embodiment of a plasma chamber to illustrate aportion of a feed ring and a connection between the portion and a powerpin.

FIG. 6 is a diagram of an embodiment of a portion of the plasma chamberto illustrate a location of the electrode with respect to the remainingcomponents of the plasma chamber.

FIG. 7 is a diagram of an embodiment of a system for illustrating thefeed ring that is coupled to an RF rod.

FIG. 8A is an embodiment of a graph to illustrate a change in anormalized etch rate of a wafer that is processed within the plasmachamber with a change in an amount of power that is supplied to theelectrode.

FIG. 8B is a diagram of a portion of the plasma chamber to illustrate achange in directionality of ion flux with a change in an amount of powerthat is supplied to the electrode.

FIG. 9A is an embodiment of a graph to illustrate a change in an etchrate of etching a substrate with a change in a capacitance of an RFfilter.

FIG. 9B is an embodiment of a graph that plots a peak voltage of theedge ring versus a capacitance of the passive RF filter of FIG. 9A.

FIG. 10 is a diagram of an embodiment of a system to illustratesynchronizing between a master RF generator and a slave RF generator.

FIG. 11 is a diagram of an embodiment of a system to illustratefrequency locking and phase locking between a master RF generator and aslave RF generator when both the master RF generator and the slave RFgenerator are operating in a continuous waveform mode.

FIG. 12 is a diagram of an embodiment of the table to illustrate acorrespondence between a factor and a variable of the RF signal that isto be modified by the slave RF generator.

FIG. 13 is a diagram of an embodiment of a system to illustratefrequency locking and phase locking between a master RF generator and aslave RF generator when both the master RF generator and the slave RFgenerator are operating in a state transition mode.

FIG. 14 is a diagram of an embodiment of a timing diagram to illustratemultiple states of RF signals generated by the master RF generator ofFIG. 13, the slave RF generator of FIG. 13, and a transistor-transistorlogic (TTL) signal.

FIG. 15 is a diagram of an embodiment of a table to illustrate acorrespondence between a factor for states S1 and S2 and the variable ofthe RF signal that is to be modified by the slave RF generator of FIG.13 for the states S1 and S2.

FIG. 16A is a diagram of an embodiment of a graph to illustrate adifference in phases of a variable associated with an output of animpedance matching circuit and a variable associated with an output ofanother impedance matching circuit.

FIG. 16B is a diagram of an embodiment of a graph to illustrate areduction in the difference in phases of the variable associated withthe outputs of the impedance matching circuits.

FIG. 16C is a diagram of an embodiment of a graph to illustrate a changein a magnitude of a voltage waveform to achieve a factor.

FIG. 17A is a diagram of an embodiment of a graph to illustrate that,during a process 1, a tilt of a plasma sheath in the edge region of theplasma chamber is controlled by controlling a magnitude of a variable ofan RF signal generated by the slave RF generator of FIG. 10.

FIG. 17B is a diagram of an embodiment of a graph to illustrate that,during a process 2, a tilt of the plasma sheath in the edge region iscontrolled by controlling the magnitude of the variable of the RF signalgenerated by the slave RF generator of FIG. 10.

DETAILED DESCRIPTION

The following embodiments describe systems and methods for controllingdirectionality of ions in an edge region of a plasma chamber by using anelectrode within a coupling ring and for achieving a pre-determinedfactor associated with an edge region within a plasma chamber bysynchronizing main and edge radio frequency (RF) generators. It will beapparent that the present embodiments may be practiced without some orall of these specific details. In other instances, well known processoperations have not been described in detail in order not tounnecessarily obscure the present embodiments.

FIG. 1 is a diagram of an embodiment of a plasma system 100 toillustrate controlling directionality of ions in an edge region 102 of aplasma chamber 104 by using a coupling ring 112. The plasma system 100includes an x megahertz (MHz) RF generator, a z MHz RF generator, an x1kilohertz (kHz) RF generator, an impedance matching circuit (IMC) 108,another IMC 113, and the plasma chamber 104. The plasma chamber 104includes an edge ring 110, the coupling ring 112, and a chuck 114, e.g.,an electrostatic chuck (ESC), etc. The edge ring 110 performs manyfunctions, including positioning the substrate 120 on the chuck 114 andshielding the underlying components, of the plasma chamber 104, notprotected by substrate 120 from being damaged by the ions of the plasmaformed within the plasma chamber 104. The chuck 114, e.g., a lowerelectrode, etc., is made of a metal, e.g., anodized aluminum, alloy ofaluminum, etc.

The coupling ring 112 is located below the edge ring 110 and is coupledto the edge ring 110. The coupling ring 112 is made from an electricalinsulator material, e.g., a dielectric material, ceramic, glass,composite polymer, aluminum oxide, etc. The edge ring 110 confinesplasma to an area above a substrate 120 and/or protects the chuck 114from erosion by the plasma. The edge ring 110 is made from one or morematerials, e.g., crystal silicon, polycrystalline silicon, siliconcarbide, quartz, aluminum oxide, aluminum nitride, silicon nitride, etc.Both the edge ring 110 and the coupling ring 112 are located besides thechuck 114. An edge of the substrate 120 is placed over the edge ring 110and the edge of the edge ring 110 is located in the edge region 102. Asan example, the edge region 102 extends from the edge ring 110 by apre-determined distance of 10 millimeters to 15 millimeters along aradius of the chuck 114 from an edge of the chuck 114. The plasmachamber 104 has a chamber wall 115, which is coupled to ground.

The x MHz RF generator is coupled via an RF cable 126, the IMC 108 andan RF transmission line 122 to the coupling ring 112. Moreover, the x1kHz RF generator and the z MHz RF generators are coupled via the IMC 113and another RF transmission line 124 to the chuck 114. An RFtransmission line includes an RF rod and an insulator sleeve thatsurrounds the RF rod. The x1 kHz RF generator is coupled to the IMC 113via an RF cable 128 and the z MHz RF generator is coupled to the IMC 113via an RF cable 130. Examples of the x1 kHz RF generator include agenerator having a frequency of operation of 400 kHz, a generator havinga frequency of operation ranging between 360 kHz and 440 kHz, etc.Examples of the x MHz RF generator include a generator having afrequency of operation of 2 MHz, a generator having a frequency ofoperation of 27 MHz etc. Example of the z MHz RF generator include agenerator having a frequency of operation of 27 MHz, a generator havinga frequency of operation of 60 MHz, etc.

The x1 kHz generates an RF signal and sends the RF signal to the IMC113. Similarly, the z MHz RF generator generates an RF signal and sendsthe RF signal to the IMC 113. The IMC 113 matches an impedance of aload, e.g., the RF transmission line 124, the plasma chamber 104, etc.,coupled to an output of the IMC 113 with that of a source, e.g., the RFcable 128, the RF cable 130, the x1 kHz RF generator and the z MHz RFgenerator, etc., coupled to inputs of the IMC 113 to provide a modifiedRF signal at its output. Similarly, the IMC 108 matches an impedance ofa load, e.g., the plasma chamber 104, the RF transmission line 112,etc., that is coupled an output of the IMC 108 with that of a source,e.g., the x MHz RF generator, the RF cable 126, etc., that is coupled aninput of the IMC 108 to provide a modified RF signal at its output.

The modified RF signal at the output of the IMC 113 is sent to the chuck114 to modify an impedance of plasma, e.g., to generate and maintainplasma, etc., within the plasma chamber 104 at a center region 132 ofthe plasma chamber 104. The center region 132 is located adjacent to theedge region 102 and is surrounded by the edge region 102. The centerregion extends from one end of the edge region 102 via a center of thechuck 114 to an opposite end of the edge region 102. Moreover, themodified RF signal at the output of the IMC 108 is sent to the couplingring 112 to modify an impedance of plasma and a directionality of ionswithin the edge region 102 of the plasma chamber 104. The plasma isgenerated or maintained when one or more process gases, e.g., oxygencontaining gas, fluorine containing gas, etc., are supplied via an upperelectrode 121 to the center region 132 of the plasma chamber 104.

The upper electrode 121 faces the chuck 114 and a gap is formed betweenthe upper electrode 121 and the chuck 114. The upper electrode 121 islocated within the plasma chamber 104 and is made of a conductivematerial. The plasma within the plasma chamber 104 is used to processthe substrate 120. For example, the plasma is used to etch the substrate120, to deposit materials on the substrate 120, to clean the substrate120, etc.

In some embodiments, the plasma chamber 104 includes additional parts,e.g., an upper electrode extension that surrounds the upper electrode121, a dielectric ring between the upper electrode 121 and the upperelectrode extension, confinement rings located besides edges of theupper electrode 121 and the edge ring 110 to surround the gap within theplasma chamber 104, etc.

In various embodiments, the RF signal that is generated by the x MHz RFgenerator is synchronized with the RF signal that is generated by the x1kHz RF generator and with the RF signal that is generated by the z MHzRF generator. For example, at a time the RF signal generated by the xMHz RF generator is pulsed from a low state to a high state, the RFsignal that is generated by the x1 kHz RF generator is pulsed from thelow state to the high state, and the RF signal that is generated by thez MHz RF generator is pulsed from the low state to the high state. Asanother example, at a time the RF signal generated by the x MHz RFgenerator is pulsed from the high state to the low state, the RF signalthat is generated by the x1 kHz RF generator is pulsed from the highstate to the low state, and the RF signal that is generated by the z MHzRF generator is pulsed from the high state to the low state. The highstate for an RF signal has a higher level, e.g., root mean square value,peak-to-peak amplitude, etc., of power of the RF signal compared to thelow state for the RF signal.

In some embodiments, the RF signal that is generated by the x MHz RFgenerator is not synchronized with the RF signal that is generated bythe x1 kHz RF generator, or is not synchronized with the RF signal thatis generated by the z MHz RF generator, or is not synchronized with theRF signal that is generated by the x1 kHz RF generator and is notsynchronized with the RF signal that is generated by the z MHz RFgenerator.

FIG. 2A is a diagram of an embodiment of a system 200 to illustratecoupling of an electrode 202 within the coupling ring 112 to the IMC 108via an RF filter 208 and providing active power to the electrode 202.The RF filter 208 reduces an amount of RF current from reaching the x1kHz RF generator or the x MHz RF generator that is coupled to the RFfilter 208 via the IMC 108 to prevent any damage by RF power of the RFcurrent to the x1 kHz RF generator or the x MHz RF generator and anycomponent of an RF delivery system between IMC 108 and the electrode202. As an example, the RF filter 208 includes one or more capacitors,or one or more inductors, or a combination of the capacitors andinductors. The RF current is generated by the plasma within the plasmachamber 206.

The system 200 includes a plasma chamber 206, which is an example of theplasma chamber 104 (FIG. 1). The system 200 further includes the x MHzRF generator or the x1 kHz RF generator, the IMC 108, and the RF filter208. The x MHz RF generator or the x1 kHz RF generator is coupled viathe RF cable 126 to the IMC 108, which is coupled via the RFtransmission line 122 to the RF filter 208. The RF filter 208 is coupledvia a power pin 204 to the electrode 202. The electrode 202 is embeddedwithin the coupling ring 112. For example, no portion of the electrode202 is exposed outside the coupling ring 112. As another example, theelectrode 202 is embedded within the coupling ring 112 to be closer toan upper surface 212 of the coupling ring 112 compared to a lowersurface 214 of the coupling ring 112. The upper surface 212 is adjacentto the edge ring 110 and the lower surface 214 is adjacent to aninsulator ring 216 of the plasma chamber 206. The insulator ring 216 islocated below the coupling ring 112 and is made of an electricalinsulating material, e.g., quartz, etc.

The power pin 204 includes a coax cable 220 and a sleeve 222. The sleeve222 covers the coax cable 220 to insulate the coax cable 220 fromelectrical fields surrounding the coax cable 220. The sleeve 222 is madeof an electrical insulator material, e.g., plastic, glass, a combinationof plastic and glass, etc. The power pin 204 is coupled to the electrode202 and is coupled via a feed ring to an RF transmission line, which iscoupled to the RF filter 208. As an example, the feed ring is made of aconductive metal, e.g., aluminum, copper, etc. A portion of the powerpin 204 is located besides the insulator ring 216, a facilities plate224, and the remaining portion of the power pin 204 is surrounded by thecoupling ring 112. The facilities plate 224 is made from a metal, e.g.,aluminum, etc.

The facilities plate 224 is located below the chuck 114 and is coupledto the RF transmission line 124. Multiple ground rings 226, which aremade of a metal, e.g., aluminum, etc., surround a portion of aninsulator ring 228 and the insulator ring 216, and are connected toground. The insulator ring 228 is made from an insulating material,e.g., quartz, etc., and protects the edge ring 110 from being coupledwith direct current (DC) power.

The plasma chamber 206 further includes the upper electrode 121 thatfaces the chuck 114. A gap 232 is formed between the upper electrode 121and the chuck 114. Plasma is formed within the gap 232 for processingthe substrate 120. Multiple confinement rings 238 are stacked tosurround the gap 232 and a portion of the upper electrode 121. Theconfinement rings 238 are opened or closed via a motor mechanism tocontrol pressure within the gap 232 and/or to control an amount ofplasma flowing out from the gap 232 to one or more vacuum pumps locatedbelow the plasma chamber 206. A cover ring 241, e.g., a quartz coverring, etc., is overlaid on top of the ground rings 226 to protect theground rings 226 from RF power of the plasma.

The x MHz RF generator or the x1 kHz RF generator supplies an RF signalto the IMC 108. The IMC 108 matches an impedance of a load, e.g., the RFtransmission line 122, the RF filter 208, and the plasma chamber 206with that of a source, e.g., the RF cable 126 and the x MHz RF generatoror the x1 kHz RF generator, etc., to generate a modified RF signal. Themodified RF signal passes via RF transmission line 122, the RF filter208, the feed ring and the power pin 204 to the electrode 202. Thereception of the modified RF signal by the electrode 202 changesimpedance of the plasma within the edge region 102, a portion of whichis located within the gap 232. The change in impedance is used to changea directionality of ion flux within the edge region 102 to controlplasma processing, e.g., etching, deposition, cleaning, etc., of thesubstrate 120 within the edge region 102.

In one embodiment, the system 200 excludes the RF filter 208 and IMC 108is coupled via the RF transmission line 122 to the feed ring.

FIG. 2B is a diagram of an embodiment of a system 250 to illustrateproviding passive power control to the electrode 202 embedded within thecoupling ring 112. The system 250 is the same as the system 200 exceptthat the system 250 includes an RF filter 207 that is coupled to the RFfilter 208 via an RF cable 254 at its output and is coupled to ground.The RF filter 207 includes one or more capacitors, or one or moreinductors, or a combination of the capacitors and inductors. Forexample, the RF filter 207 includes a capacitor in parallel with aninductor. As another example, the RF filter 207 includes a capacitor. Asyet another example, the RF filter 207 includes a capacitor in serieswith an inductor. In one embodiment, one or more capacitors of the RFfilter 207 are variable and one or more inductors of the RF filter 207are variable.

The RF filter 207 provides an impedance path to ground to an RF signalthat is received from the plasma within the edge region 102. An RFsignal is generated from the plasma within the edge region 102 and flowsvia the edge ring 110 and the capacitance between the electrode 202 andthe edge ring 110 to the electrode 202, which outputs an RF signal. TheRF signal from the electrode 202 passes through the power pin 204 andthe feed ring to the RF filter 208. The RF filter 208 filters out any DCpower within the RF signal to output a filtered RF signal. The filteredRF signal passes via the RF cable 254 and the RF filter 207 to ground. Acapacitance, or an inductance, or a combination of the capacitance andinductance of the RF filter 207 determines an amount of the filtered RFsignal that flows to ground to modify the impedance of the plasma withinthe edge region 102 to further control the directionality of the ionflux in the edge region 102.

In various embodiments, the RF filter 207 filters a portion of the RFsignal that is received from the plasma within the edge region 102 tooutput a filtered signal via the RF transmission line 254 to the RFfilter 208. The portion of the RF signal flows to the ground that iscoupled to the RF filter 207. The filtered signal received by the RFfilter 208 via the RF transmission line 254 is filtered by the RF filter208 to remove DC power to output a filtered signal to the coax cable 220of the power pin 204. The filtered signal is provided via the coax cable220 to the electrode 202 to change a capacitance between the electrode202 and the edge ring 110. The capacitance is changed to change animpedance of plasma within the edge region 102.

In some embodiments, the RF filter 208 is excluded and the RF filter 207is coupled to the power pin 204 via the RF transmission line 254.

FIG. 3A is a diagram of an embodiment of a system 300 to illustratetuning of power supplied by the x MHz RF generator or the x1 kHz RFgenerator to control the impedance of the plasma within the edge region102 to further control directionality of the ion flux in the edge region102. The system 300 is the same as the system 200 of FIG. 2A except thatthe system 300 further includes a planar ion flux probe 302, ameasurement sensor 304 and a host computer system 306. An example of theplanar ion flux probe is a Langmuir probe. Examples of the host computersystem 306 include a computer, a tablet, a smart phone, etc. Examples ofthe measurement sensor 304 include a complex voltage sensor or a complexcurrent sensor.

The planar ion flux probe 302 is inserted via an opening in the upperelectrode 121 and has a spacer between a conductive portion, e.g.,silicon, etc., of the ion flux probe 302 and the upper electrode 121.The planar ion flux probe 302 has a portion, e.g., a cylindricalportion, a polygonal portion, etc., that has a surface that is exposedto the plasma associated with the edge region 102. The planar ion fluxprobe 302 is coupled via an RF cable 308 to the measurement sensor 304,which is coupled via a transfer cable 310, e.g., a serial transfercable, a parallel transfer cable, a Universal Serial Bus (USB) cable,etc., to the host computer system 306. The host computer system 306 iscoupled via a transfer cable 312, e.g., a serial transfer cable, aparallel transfer cable, a USB cable, etc., to the x MHz RF generator orthe x1 kHz RF generator. A serial transfer cable is used to transferdata serially, e.g., one bit at a time, etc. A parallel transfer cableis used to transfer data in a parallel manner, e.g., multiple bits at atime, etc.

The planar ion flux probe 302 measures ion flux, e.g., an amount of ionflow per unit surface area of the ion flux probe 302, an amount ofcurrent per unit surface area of the ion flux probe 302, etc., of theplasma associated with the edge region 102 to generate an RF signal. TheRF signal passes via the RF cable 308 to the measurement sensor 304,which measures a complex voltage or a complex current of the RF signal.The measurement sensor 304 outputs the measured complex voltage or themeasured complex current as data via the transfer cable 310 to the hostcomputer system 306. The host computer 306 includes a processor and amemory device. Examples of the processor include a central processingunit (CPU), a controller, an application specific integrated circuit(ASIC), or a programmable logic device (PLD), etc. Examples of thememory device include a read-only memory (ROM), a random access memory(RAM), a hard disk, a volatile memory, a non-volatile memory, aredundant array of storage disks, a Flash memory, etc.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the x MHz RF generator or the x1 kHz RFgenerator that is coupled to the IMC 108 based on the measured complexvoltage or the measured complex current. For example, a correspondence,e.g., a one-to-one relationship, an association, a mapping, etc.,between a pre-determined complex voltage or a pre-determined complexcurrent and the power that is supplied by the x MHz RF generator or thex1 kHz RF generator is stored in the memory device that is coupled tothe processor. The pre-determined complex voltage or the pre-determinedcomplex current corresponds to, e.g., has a one-to-one relationshipwith, is mapped to, etc., a pre-determined amount of ion flux to begenerated within the edge region 102, and the relationship is stored inthe memory device of the host computer system 306. The processordetermines from the measured complex current that the measured complexcurrent does not match or is not within a pre-determined range from thepre-determined complex current to be achieved. The processor determinesbased on the correspondence between the pre-determined complex currentand an amount of power to be supplied by the x MHz RF generator or thex1 kHz RF generator the amount of power. The processor generates acontrol signal indicating to the x MHz RF generator or the x1 kHz RFgenerator that the amount of power is to be supplied by the x MHz RFgenerator or the x1 kHz RF generator.

In one embodiment, the processor determines from the measured complexvoltage that the measured complex voltage does not match or is notwithin a pre-determined range from the pre-determined complex voltage tobe achieved. The processor determines based on the correspondencebetween the pre-determined complex voltage and the amount of power to besupplied by the x MHz RF generator or the x1 kHz RF generator the amountof power. The processor generates a control signal indicating to the xMHz RF generator or the x1 kHz RF generator that the amount of power isto be supplied by the x MHz RF generator or the x1 kHz RF generator.

Upon receiving the amount of power, the x MHz RF generator or the x1 kHzRF generator generates and supplies and RF signal having the amount ofpower via the RF cable 126 to the IMC 108. The IMC 208 matches animpedance of the load coupled to the IMC 208 with that of the sourcecoupled to the IMC 108 to generate a modified RF signal from the RFsignal received from the x MHz RF generator or the x1 kHz RF generator.The modified RF signal is provided to the electrode 202 via the RFfilter 208, the feed ring coupled to the RF filter 208, and the coaxcable 220. The capacitance between the electrode 202 and a lower surfaceof the edge ring 110 changes when the electrode 202 receives themodified RF signal to change an impedance of the plasma within the edgeregion 102 to further modify a direction of the ion flux within the edgeregion 102.

FIG. 3B is a diagram of an embodiment of a system 320 to illustratetuning of the RF filter 207 to control the impedance within the edgeregion 102 to further control directionality of the ion flux within theedge region 102. The system 320 is the same as the system 250 (FIG. 2B)except that the system 320 includes the planar ion flux probe 302, themeasurement sensor 304, the host computer system 306, a power supply328, and a motor 322, e.g., a DC motor, an alternating current (AC)motor, etc. Examples of the power supply 328 include an AC power supplyor a DC power supply. The power supply 328 is coupled to the hostcomputer system 306 via a transfer cable 324. Moreover, the motor 322 iscoupled to the power supply 328 via a cable 330 and is coupled to the RFfilter 207 via a connection mechanism 326. Examples of the connectionmechanism 326 include one or more rods, one or more gears, or acombination thereof. The connection mechanism 326 is connected to acircuit component, e.g., an inductor, a capacitor, etc., of the RFfilter 207 to change a parameter, e.g., capacitance, inductance, etc.,of the circuit component. For example, the connection mechanism 326rotates to change an area between two parallel plates of a capacitor ofthe RF filter 207 and/or a distance between the plates. As anotherexample, the connection mechanism 326 to displace a core surrounded by acoil of an inductor of the RF filter 207 to change an inductance of theinductor.

The processor determines from the complex current, measured by themeasurement sensor 304, that the measured complex current does not matchor is not within the pre-determined range from the pre-determinedcomplex current to be achieved. The processor determines based on thecorrespondence among the pre-determined complex current, an amount ofpower, e.g., DC power, AC power, etc., to be supplied by the powersupply 328 and a pre-determined capacitance of the RF filter 207 to beachieved, the amount of power. The processor generates a control signalindicating to the power supply 328 that the amount of power is to besupplied by the power supply 328 to achieve the pre-determinedcapacitance of the RF filter 207.

In one embodiment, the processor determines from the measured complexvoltage that the measured complex voltage does not match or is notwithin the pre-determined range from the pre-determined complex voltageto be achieved. The processor determines based on the correspondenceamong the pre-determined complex voltage, the pre-determined capacitanceof the RF filter 207 to be achieved, and the amount of power to besupplied by the power supply 328, the amount of power. The processorgenerates a control signal indicating to the power supply 328 that theamount of power is to be supplied by the power supply 328.

The control signal is sent via the transfer cable 324 to the powersupply 328. Upon receiving the amount of power, the power supply 328generates and supplies the amount of power via the cable 330 to themotor 322. A stator of the motor 322 receives the amount of power togenerate an electric field, which rotates a rotor of the motor 322. Therotation of the rotor rotates the connection mechanism 326 to change theparameter of the RF filter 207 to achieve the pre-determinedcapacitance. The change in the parameter, e.g., the capacitance, etc.,changes an amount of RF power that flows via the RF filter 207 to theground coupled to the RF filter 207 to further change the capacitancebetween the electrode 202 and the edge ring 110. The capacitance betweenthe electrode 202 and the edge ring 110 is changed via the RF cable 254,the RF filter 208, the feed ring coupled to the RF filter 208, and thecoax cable 220. The change in the capacitance changes an amount of powerof the filtered signal flowing from the RF filter 207 to the RF filter208 via the RF transmission line 254. The change in the amount of powerchanges an impedance of the plasma within the edge region 102 to furthermodify the directionality of the ion flux within the edge region 102.

FIG. 3C is a diagram of an embodiment of a system 350 to illustrate useof DC bias to tune power supplied by the x MHz RF generator or the x1kHz RF generator to control the impedance of the plasma within the edgeregion 102 to further control directionality of the ion flux in the edgeregion 102. The system 350 is the same as the system 300 (FIG. 3A)except that the system 350 includes a measurement sensor 354, and a DCbias probe 352 instead of the planar ion flux probe 302 (FIG. 3A) andthe measurement sensor 304 (FIG. 3A). An example of the measurementsensor 354 is a DC bias voltage sensor.

A portion of the DC bias sensor 352 is extended into the edge ring 110via an opening in the edge ring 110 and the remaining portion of the DCbias sensor 352 is extended into the insulator ring 228 via an openingin the insulator ring 228. The DC bias sensor 352 is connected to themeasurement sensor 354 via a cable 356 to the measurement sensor 354.The measurement sensor 354 provides a measurement of a DC bias, e.g., aDC bias voltage, etc., that is generated by RF power of the edge ring110. The RF power of the edge ring 110 is based on RF power of theplasma within the edge region 102. The measurement sensor 354 isconnected to the host computer system 306 via the transfer cable 310.

The DC bias probe 352 senses a DC bias voltage of the edge ring 110 togenerate an electrical signal and the DC bias voltage is induced by RFpower of the plasma in the edge region 102. The electrical signal issent via the cable 356 to the measurement sensor 354, which measures theDC bias voltage based on the electrical signal. An amount of themeasured DC bias voltage is sent as data from the measurement sensor 354via the transfer cable 310 to the host computer system 306.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the x MHz RF generator or the x1 kHz RFgenerator that is coupled to the IMC 108 based on the measured DC biasvoltage. For example, a correspondence, e.g., a one-to-one relationship,an association, a mapping, etc., between a DC bias voltage and an amountof power that is supplied by the x MHz RF generator or the x1 kHz RFgenerator in the memory device that is coupled to the processor. Theprocessor of the host computer system 306 determines from the measuredDC bias voltage that the measured DC bias voltage does not match or isnot within a pre-determined range from a pre-determined DC bias voltageto be achieved. The processor determines based on the correspondencebetween the pre-determined DC bias voltage and an amount of power to besupplied by the x MHz RF generator or the x1 kHz RF generator the amountof power. The processor generates a control signal indicating to the xMHz RF generator or the x1 kHz RF generator that the amount of power isto be supplied by the x MHz RF generator or the x1 kHz RF generator.

Upon receiving the amount of power, the x MHz RF generator or the x1 kHzRF generator generates and supplies an RF signal having the amount ofpower via the RF cable 126 to the IMC 108. The IMC 108 matches animpedance of the load coupled to the IMC 208 with that of the sourcecoupled to the IMC 108 to generate a modified RF signal from the RFsignal received from the x MHz RF generator or the x1 kHz RF generator.The modified RF signal is provided to the electrode 202 via the RFfilter 208, the feed ring coupled to the RF filter 208, and the coaxcable 220. The capacitance between the electrode 202 and the edge region110 changes when the electrode 202 receives the modified RF signal tochange an impedance of the plasma within the edge region 102 to furthermodify a direction of the ion flux within the edge region 102.

FIG. 3D is a diagram of an embodiment of a system 370 to illustrate useof DC bias voltage to tune the RF filter 207 to control the impedance ofthe plasma within the edge region 102 to further control directionalityof the ion flux in the edge region 102. The system 370 is the same asthe system 320 (FIG. 3B) except that the system 370 includes themeasurement sensor 354, and the DC bias probe 352 instead of the planarion flux probe 302 (FIG. 3B) and the measurement sensor 304 (FIG. 3B).As explained above with reference to FIG. 3C, the measurement sensor 354outputs the measured DC bias voltage to the host computer system 306 viathe transfer cable 310.

The processor of the host computer system 306 determines an amount ofpower to be supplied by the power supply 328 based on the measured DCbias voltage. For example, a correspondence, e.g., a one-to-onerelationship, an association, a mapping, etc., between a DC bias voltageand an amount of power that is supplied by the power supply 328 isstored in the memory device that is coupled to the processor. Theprocessor of the host computer system 306 determines from the measuredDC bias voltage that the measured DC bias voltage does not match or isnot within a pre-determined range from a pre-determined DC bias voltageto be achieved. The processor determines based on the correspondencebetween the pre-determined DC bias voltage and the amount of power to besupplied by the power supply 328 the amount of power. The processorgenerates a control signal indicating to the power supply 328 that theamount of power is to be supplied by the power supply 328.

The control signal is sent via the transfer cable 324 to the powersupply 328. Upon receiving the amount of power, as described above withreference to FIG. 3B, the power supply 328 generates and supplies theamount of power via the cable 330 to the motor 322, which rotates tochange the parameter of the RF filter 207, and the change in theparameter changes the capacitance between the electrode 202 and the edgering 110. The capacitance between the electrode 202 and the edge ring110 is changed to change the impedance of the plasma within the edgeregion 102 to further change the directionality of the ion flux withinthe edge region 102.

In some embodiments, a current, e.g., a complex current, etc., or avoltage, e.g., a DC bias voltage, a complex voltage, etc., is referredto herein as a variable.

FIG. 4A is a diagram of an embodiment of a mesh electrode 402, which isembedded within the coupling ring 112 (FIG. 1). The mesh electrode 402includes multiple crossings of wires to form a net-like structure and isan example of the electrode 202 (FIG. 2A). The mesh electrode 402 ismade of a metal, e.g., aluminum, copper, etc.

FIG. 4B is a diagram of an embodiment of a ring shaped electrode 404,which is an example of the electrode 202 (FIG. 2A). The ring shapedelectrode 404 is tubular in structure or flat, e.g., plate-shaped, etc.,in structure. The ring shaped electrode 404 is made of a metal, e.g.,aluminum, copper, etc.

FIG. 5 is a diagram of an embodiment of a plasma chamber 500 toillustrate a portion of a feed ring 502 and a connection between theportion and the power pin 204. The plasma chamber 500 is an example ofthe plasma chamber 104 (FIG. 1). The feed ring 502 is connected at oneend 506 to an RF rod 504 of the RF transmission line 122 (FIG. 1) and atan opposite end 508 to the coax cable 220 of the power pin 204. Theplasma chamber 500 includes an RF rod 510 of the RF transmission line124 (FIG. 1). The RF rod 510 is situated within an RF cylinder 512,which is surrounded at its bottom portion by another RF cylinder 514.

The modified RF signal that is sent via the RF transmission line 122from the IMC 108 is sent via the RF rod 504 of the RF transmission line122 and the end 506 to the feed ring 502. A portion of the modified RFsignal transfers from the end 506 via the end 508 and the coax cable 220to the electrode 202 embedded within the coupling ring 112 for providingcapacitive coupling between the electrode 202 and the edge ring 110.

In some embodiments in which the passive power is provided to theelectrode 202, the RF rod 504 is of the RF transmission line 254 insteadof the RF transmission line 122 (FIG. 1). The RF transmission line 254couples the RF filter 207 to the RF filter 208 (FIG. 2B).

In various embodiments, the RF filter 208 is coupled to the RF rod 504of the RF transmission line 254 and is coupled to the feed ring 502. Forexample, in an embodiment in which passive RF power is flowing from theground that is connected to the RF filter 207 towards the electrode 202,an input of the RF filter 208 is coupled to the RF rod 504 and an outputof the RF filter 208 is coupled to the feed ring 502. As anotherexample, in an embodiment in which passive RF power from the edge region102 is flowing to the ground that is coupled to the RF filter 207, aninput of the RF filter 208 is coupled to the feed ring 502 and an outputof the RF filter 208 is coupled to the RF rod 504. As yet anotherexample, the RF filter 208 is coupled to the end 506 of the arm 716 andis coupled to the RF rod 504.

In an embodiment in which the active power is used, an input of the RFfilter 208 is coupled to the RF rod 504 that is further coupled to theIMC 108 (FIG. 2A) and an output of the RF filter 208 is coupled to thefeed ring 502.

FIG. 6 is a diagram of an embodiment of a portion 650 of a plasmachamber, which is an example of the plasma chamber 104 (FIG. 1), toillustrate a location of the electrode 202 with respect to the remainingcomponents of the plasma chamber. The portion 650 include an insulatorring 652 of the plasma chamber. The insulator ring 652 surrounds aportion of an insulator ring 604 and a portion of the insulator ring 652is located below the insulator ring 604. The insulator ring 604 islocated below another insulator ring 654.

The insulator ring 654 is adjacent to the coupling ring 112 and is belowan insulator ring 612 that surrounds the edge ring 110. The couplingring 112 is adjacent to the chuck 114. The edge ring 110 is overlaid ontop of a portion 608 of the coupling ring 112. The portion 608 of thecoupling ring 112 acts like a dielectric between the electrode 202 and alower surface of the edge ring 110 so that capacitive coupling isestablished between the electrode 202 and the edge ring 110. The portion608 creates a dielectric between the edge ring 110 and a remainingportion 606 of the coupling ring 112. The insulator ring 612 issurrounded by a movable ground ring 614, which is coupled to ground. Themovable ground ring 614 is located on top of a fixed ground ring 616,which is also coupled to ground.

The insulator 654 is located adjacent to the chuck 114, the facilitiesplate 224, and the coupling ring 112 on its inner side and to the fixedground ring 616 at its outer side. Moreover, the insulator ring 604 islocated below the facilities plate 224, which supports the chuck 114.The fixed ground ring 616 is adjacent to and surrounds the insulatorring 654 and on top of the insulator ring 652.

The confinement rings 238 (FIGS. 2A & 2B) include a confinement ringportion 656 and a confinement ring horizontal portion 658, e.g., aslotted ring, etc. The upper electrode 121 is surrounded by an upperelectrode extension 660.

The gap 232 formed between the upper electrode 121 and the chuck 114 issurrounded by the upper electrode 121, the upper electrode extension660, the confinement ring portion 656, the confinement ring horizontalportion 658, the insulator ring 612, the edge ring 110, and the chuck114.

The coupling ring 112 is surrounded by the edge ring 110, the insulatorring 654, and the chuck 114. For example, the coupling ring 112 isadjacent to the chuck 114, the edge ring 110, and the insulator ring654. As another example, the edge ring 110 is located on top of thecoupling ring 112 in which the electrode 202 is embedded, the chuck 114is located adjacent to an inner side of the coupling ring 112, and theinsulator ring 654 is located adjacent to an outer side of the couplingring 112. The coax cable 220 passes via the insulator ring 604 and theinsulator ring 654 to be connected to the electrode 202 located withinthe portion 606 of the coupling ring 112.

FIG. 7 is a diagram of an embodiment of a system 700 for illustratingthe feed ring 502 that is coupled to the RF rod 504. The feed ring 502includes a circular portion 708 that is connected to multiple arms 710,712, 714, and 716. The circular portion 708 is flat or is ring-shaped.The arm 716 is connected at the end 506 to the RF rod 504 and at anopposite end 718 to the circular portion 708. For example, the arm 716is fitted to the RF rod 504 at the end 506 via a fitting mechanism,e.g., a screw, a bolt, a clamp, a nut, or a combination thereof, etc.Similarly, the arm 710 is connected at an end 720 to a power pin 702.For example, the arm 710 is fitted to the power pin 702 at the end 720via the fitting mechanism. The power pin 702 is the same in structureand function as that of the power pin 204. For example, the power pin702 includes a coax cable and a sleeve that surrounds at least a portionof the coax cable. The arm 710 is connected at an opposite end 722 tothe circular portion 708.

Moreover, the arm 712 is connected at an end 724 to a power pin 704,which is the same in structure and function as that of the power pin204. For example, the power pin 704 includes a coax cable and a sleevethat surrounds at least a portion of the coax cable. As an example, thearm 712 is fitted to the power pin 704 at the end 724 via the fittingmechanism. The arm 712 is connected at an opposite end 726 to thecircular portion 708.

Furthermore, the arm 714 is connected at the end 508 to the power pin204. The arm 714 is connected at an opposite end 728 to the circularportion 708. The arm 710 extends from the circular portion 708 toconnect to the coax cable of the power pin 702, the arm 712 extends fromthe circular portion 708 to connect to the coax cable of the power pin704, and the arm 714 extends from the circular portion 798 to connect tothe coax cable 220 of the power pin 204. The power pin 702, e.g. thecoax cable of the power pin 702, etc., is connected at a point 730 tothe electrode 202 embedded within the coupling ring 112. Moreover, thepower pin 704, e.g. the coax cable of the power pin 704, etc., isconnected at a point 732 to the electrode 202, and the power pin 204,e.g., the coax cable 220, etc., is connected at a point 734 to theelectrode 202.

The modified RF signal that is received via the RF rod 504 and theimpedance matching circuit 108 (FIG. 1) is sent via the arm 716 to thecircular portion 708, and is divided between the arms 710, 712, and 714.A portion of power of the modified RF signal passes via the arm 710 andthe power pin 702, e.g. the coax cable of the power pin 702, etc., tothe electrode 202, another portion of the power of the modified RFsignal passes via the arm 712 and the power pin 704, e.g. the coax cableof the power pin 704, etc., to the electrode 202, and yet anotherportion of the power passes via the arm 714 and the power pin 204, e.g.,the coax cable 220, etc., to the electrode 202.

In some embodiments, the feed ring 502 includes any other number ofarms, e.g., two, one, four, five, etc., that extend from the circularportion 708 to connect to the electrode 202 within the coupling ring112.

In various embodiments, instead of the circular portion 708, a portionof another shape, e.g., oval, polygonal, etc., is used.

FIG. 8A is an embodiment of a graph 800 to illustrate a change in anormalized etch rate of a wafer that is processed within the plasmachamber 104 with a change is an amount of power that is supplied to theelectrode 202 (FIG. 2A). The wafer is an example of the substrate 120(FIG. 1). The graph 800 plots the normalized etch rate versus a radiusof the wafer when the chuck 114 of the plasma chamber 104 (FIG. 1) issupplied with RF power from the x1 kHz and z MHz RF generators via theIMC 113 (FIG. 1), and the electrode 202 is supplied with RF power fromthe x MHz RF generator via the IMC 108 (FIG. 1).

The graph 800 includes three plots 802, 804, and 806. The plot 802 isgenerated when an amount of RF power P1 of the x MHz RF generator issupplied via the IMC 108 to the electrode 202. The plot 804 is generatedwhen an amount of RF power P2 of the x MHz RF generator is supplied viathe IMC 108 to the electrode 202 and the plot 806 is generated when anamount of RF power P3 of the x MHz RF generator is supplied via the IMC108 to the electrode 202. The power P3 is greater than the power P2,which is greater than the power P1.

FIG. 8B is a diagram of a portion of the plasma chamber 104 (FIG. 1) toillustrate a change in directionality of ion flux with a change in theamount of power that is supplied to the electrode 202. When the amountof power P1 is supplied to the electrode 202, a directionality 812 a ofion flux 810 is such that the ions are not vertically directed towardsthe substrate 120 but are directed at a negative angle −θ, with respectto a 90 degree ion incidence angle, which is perpendicular to a diameterof the coupling ring 112. The angle θ is measured with respect to avertical axis perpendicular to the diameter of the coupling ring 112.This increases an etch rate of etching the substrate 120 in the edgeregion 102.

Moreover, when the amount of power P2 is supplied to the electrode 202,a directionality 812 b of the ion flux 810 is such that the ions arevertically directed, e.g. θ=0. The power P2 increases voltage of theedge ring 110 compared to the power P1. This decreases an etch rate ofetching the substrate 120 in the edge region 102 compared to when theamount of power P1 is supplied. The etch rate is decreased to achieve auniform etch rate at the edge region 102 and to achieve a flat plasmasheath at the edge region 102. For example, there is little or nodifference between levels of a plasma sheath over the wafer and over theedge ring 110.

Also, when the amount of power P3 is supplied to the electrode 202, adirectionality 812 c of the ion flux 810 is such that the ions are notvertically directed towards the substrate 120 but are directed at apositive angle θ. This decreases an etch rate of etching the substrate120 in the edge region 102 compared to when the amount of power P2 issupplied. By controlling an amount of power supplied to the electrode202, a directionality of the ion flux 810 is controlled via the powerpin 204 (FIG. 2A) and the electrode 202.

In some embodiments, instead of increasing the power that is supplied bythe electrode 202, an amount of capacitance of the RF filter 207 (FIG.2B) is increased to change the angle θ from a negative value to zerofurther to a positive value to control directionality of the ion flux810.

FIG. 9A is an embodiment of a graph 900 to illustrate a change in anetch rate of etching the substrate 120 (FIG. 1) with a change in acapacitance of the RF filter 207 (FIG. 2B). The graph 900 plots thenormalized etch rate versus the radius of the wafer for various valuesof capacitances of the RF filter 207. As a capacitance of the RF filter207 increases, an etch rate of the wafer at the edge region 102 (FIG. 1)decreases to achieve more uniformity in the etch rate.

FIG. 9B is an embodiment of a graph 902 that plots a peak voltage of theedge ring 110 (FIG. 1) versus the capacitance of the RF filter 207 (FIG.2B). As the capacitance of the RF filter 207 increases, the peak voltageof the edge ring 110 increases to change the directionality of the ionflux 810 (FIG. 8B) from negative θ to zero to positive θ.

FIG. 10 is a diagram of an embodiment of a system 1000 to illustratesynchronizing between a master RF generator 1014 and a slave RFgenerator 1012. The system 1000 includes the master RF generator 1014,the slave RF generator 1012, the IMC 108, the IMC 113, an RF generator1002, another RF generator 1018, a variable sensor 1020, a variablesensor 1022, the chuck 114, and an edge electrode 1016. An example ofthe edge electrode 1016 the coupling ring 112 or the edge ring 110 (FIG.1), or a combination thereof, etc. For example, the edge electrode 1016includes a stack of the edge ring 110 on top of the coupling ring 112.In some embodiments, when the edge electrode 1016 includes the stack,the edge electrode 1016 is referred to herein as an edge electrodestack. The edge electrode 1016 surrounds the chuck 114 for controlling aplasma sheath of the plasma formed within the edge region 102. The chuck114 is sometimes referred to herein as a main electrode. Examples ofeach of the variable sensor 1020 and the variable sensor 1022 include acomplex voltage sensor, or a complex power sensor, or a complex currentsensor, or a complex voltage and current sensor, or a complex impedancesensor.

The master RF generator 1014 has a lowest frequency of operation amongfrequencies of operation of RF generators supplying power to the chuck114 and so is a low frequency (LF) generator. For example, a frequencyof an RF signal generated by the master RF generator 1014 is a frequencylower than a frequency of the RF generator 1002 also supplying an RFsignal to the chuck 114 via the IMC 108. To illustrate, the master RFgenerator 1014 has a frequency of operation of x1 kHz and the RFgenerator 1002 has a frequency of operation of x MHz or y MHz of z MHz.As another illustration, the master RF generator 1014 has a frequency ofoperation of x MHz and the RF generator 1002 has a frequency ofoperation of y MHz of z MHz. An example of the y MHz frequency is 27 MHzwhen the x MHz frequency is 2 MHz and the z MHz frequency is 60 MHz.Similarly, the slave RF generator 1012 has a lowest frequency amongfrequencies of operation of RF generators supplying power to the edgeelectrode 1016 and so is a low frequency (LF) generator. For example, afrequency of an RF signal generated by the slave RF generator 1012 is afrequency lower than a frequency of the RF generator 1018 also supplyingan RF signal to the edge electrode 1016 via the IMC 113. To illustrate,the slave RF generator 1012 has a frequency of operation of x1 kHz andthe RF generator 1018 has a frequency of operation of x MHz or y MHz ofz MHz. As another illustration, the slave RF generator 1012 has afrequency of operation of x MHz and the RF generator 1018 has afrequency of operation of y MHz of z MHz.

The master RF generator 1014 and the RF generator 1002 are coupled toinputs 1038 and 1040 of the IMC 108 and an output 1008 of the IMC 108 iscoupled to the chuck 114 via the RF transmission line 124. For example,the master RF generator 1014 is coupled to the input 1038 of the IMC 108via an RF cable 1036 and the RF generator 1002 is coupled to the input1040 of the IMC 108 via an RF cable 1034. Similarly, the slave RFgenerator 1012 and the RF generator 1018 are coupled to inputs 1042 and1044 of the IMC 113 and an output 1010 of the IMC 113 is coupled to theedge electrode 1016 via the RF transmission line 122. For example, theslave RF generator 1012 is coupled to the input 1042 of the IMC 113 viaan RF cable 1046 and the RF generator 1018 is coupled to the input 1044of the IMC 113 via an RF cable 1048. The variable sensor 1020 is coupledat a point 1004 on the RF transmission line 124 and the variable sensor1022 is coupled at a point 1006 on the RF transmission line 122. Thevariable sensor 1020 is coupled via a transfer cable 1030 to the slaveRF generator 1012 and the variable sensor 1022 is coupled via a transfercable 1032 to the slave RF generator 1012. The master RF generator 1014is coupled to the slave RF generator 1012 via a transfer cable 1050.

The RF generator 1002 and the master RF generator 1014 generate RFsignals. The RF signal generated by the master RF generator 1014 has afrequency within a pre-set limit from, e.g., the same as, within apre-stored limit from, etc., the frequency of operation of the master RFgenerator 1014. The RF signal generated by the master RF generator 1002is supplied via the RF cable 1036 and the input 1040 to the IMC 108.Similarly, the RF signal generated by the RF generator 1002 is suppliedvia the RF cable 1034 and the input 1038 to the IMC 108. The IMC 108matches an impedance of a load, e.g., the transmission line 124 and thechuck 114, etc., coupled to the output 1008 of the IMC 108 with that ofa source, e.g., the RF cables 1034 and 1036, and the RF generators 1002and 1014, etc., coupled to the inputs 1034 and 1036 of the IMC 108 togenerate a modified RF signal. The modified RF signal is supplied viathe RF transmission line 124 to the chuck 114 with one or more of theprocess gases for generating or maintaining plasma within the plasmachamber 104 (FIG. 1).

The master RF generator 1014 provides the frequency of operation of themaster RF generator 1014 via the transfer cable 1050 to the slave RFgenerator 1012. The slave RF generator 1012 receives the frequency ofoperation of the master RF generator 1014 and determines to generate anRF signal having a frequency that is within a pre-determined range from,e.g., the same as, within a pre-stored frequency range from, etc., thefrequency of operation of the master RF generator 1014. For example, theslave RF generator 1012 receives the frequency of operation of themaster RF generator 1014 and modifies the frequency of operation of theslave RF generator 1018 to be within the pre-determined range from thefrequency of operation of the master RF generator 1014.

The RF generator 1018 and the slave RF generator 1012 generate RFsignals. The RF signal generated by the slave RF generator 1012 has thefrequency that is within the pre-determined range and is supplied viathe RF cable 1046 and the input 1042 to the IMC 113. Similarly, the RFsignal generated by the RF generator 1018 is supplied via the RF cable1048 and the input 1044 to the IMC 113. The IMC 113 matches an impedanceof a load, e.g., the RF transmission line 122 and the edge electrode1016, etc., that is coupled to the output 1010 of the IMC 113 with thatof a source, e.g., the RF cables 1046 and 1048, and the RF generators1012 and 1018, etc., that are coupled to the inputs 1042 and 1044 of theIMC 113 to generate a modified RF signal. The modified RF signal issupplied via the RF transmission line 122 to the edge electrode 1016 forcontrolling the plasma sheath within the edge region 102 of the plasmachamber 104 (FIG. 1).

Once, e.g., after, etc., the RF signal is generated by the slave RFgenerator 1012 and the modified RF signal is sent via the RFtransmission line 122 to the edge electrode 1016, the variable sensor1022 measures a value of the variable, e.g., complex power, complexvoltage, complex current, complex impedance, etc., associated with theoutput 1010 of the IMC 113, e.g., measured at the output 1010, measuredat a point on the RF transmission line 122, etc., and provides the valuevia the transfer cable 1032 to the slave RF generator 1012. It should benoted that a complex variable includes a magnitude, e.g., an amplitude,etc., of the complex variable and a phase of the complex variable.Moreover, after the RF signal is generated by the master RF generator1014 and the modified RF signal is sent via the RF transmission line 124to the chuck 114, the variable sensor 1020 measures a value of thevariable associated with the output 1008, e.g., measured at the output1008 of the IMC 108, measured at a point on the RF transmission line124, etc., and provides the value via the transfer cable 1030 to theslave RF generator 1012.

The slave RF generator 1012 compares a phase within the value of thevariable measured by the variable sensor 1022 with a phase within thevalue of the variable measured by the variable sensor 1020. In responseto the comparison, the slave RF generator 1012 modifies a phase of theRF signal generated by the slave RF generator 1012 so that the phasewithin the value of the variable measured by the variable sensor 1022 iswithin a pre-set range from, e.g., the same as, within a pre-storedphase range from, etc., the phase of the value of the variable measuredby the variable sensor 1020. To illustrate, based on the comparison, theslave RF generator 1012 changes a phase of the RF signal generated bythe slave RF generator 1012 so that the phase of the RF signal is withinthe pre-set range from the phase within the value of the variablemeasured by the variable sensor 1020.

Once the slave RF generator 1012 modifies the frequency of operation ofthe slave RF generator 1018 to be within the pre-determined range fromthe frequency of operation of the master RF generator 1014 and changesthe phase of the RF signal generated by the slave RF generator 1012 sothat the phase of the RF signal is within the pre-set range from thephase of the variable measured by the variable sensor 1020, the slave RFgenerator 1012 determines a magnitude of a variable, e.g., complexpower, complex voltage, complex current, etc., of the RF signal. Forexample, after the frequency of operation of the slave RF generator 1012is matched to the frequency of operation of the master RF generator 1014and the phase of the RF signal to be modified by the slave RF generator1012 is adjusted so that the phase of the variable associated with theoutput 1010 of the IMC 113 matches the phase of the variable associatedwith the output 1008 of the IMC 108, the slave RF generator 1012accesses a factor within a memory device within the slave RF generator1012 to determine a magnitude of the variable of the RF signal to bemodified by the slave RF generator 1012. Examples of the factor includea tilt of plasma sheath in the edge region 102, a wafer direct current(DC) bias of the edge electrode 1016, or an ellipticity of contact ofcircles at a top surface of the substrate 120, an etch rate of etchingthe substrate 120, a deposition rate of depositing materials on thesubstrate 120, etc.

It should be noted that as an example, the magnitude of the variable ofthe RF signal generated by the slave RF generator 1012 is of a differenttype from the variable associated with the outputs 1008 and 1010. Toillustrate, when the variable associated with the outputs 1008 and 1010is voltage, the magnitude of the variable of the RF signal generated bythe slave RF generator 1012 is power amplitude. As another illustration,when the variable associated with the outputs 1008 and 1010 is power,the magnitude of the variable of the RF signal generated by the slave RFgenerator 1012 is voltage amplitude. As another example, the magnitudeof the variable of the RF signal generated by the slave RF generator1012 is the same type as the variable associated with the outputs 1008and 1010. To illustrate, when the variable associated with the outputs1008 and 1010 is power, the magnitude of the variable of the RF signalgenerated by the slave RF generator 1012 is power amplitude.

The magnitude of the variable is applied by the slave RF generator 1012to generate the RF signal that is provided from the slave RF generator1012 via the RF cable 1046 and the input 1042 of the IMC 113. Moreover,the RF generator 1018 generates an RF signal and supplies the RF signalvia the RF cable 1048 and the input 1044 to the IMC 113. The IMC 113matches an impedance of the load that is coupled to the output 1010 ofthe IMC 113 with that of the source that are coupled to the inputs 1042and 1044 of the IMC 113 to generate a modified RF signal. The modifiedRF signal is sent via the RF transmission line 124 to the edge electrode1016 for controlling the factor associated with the plasma sheath at theedge region 102.

In various embodiments, the variable sensor 1020 is connected to theoutput 1008 and the variable sensor 1022 is connected to the output1010. In some embodiments, the variable sensor 1020 is coupled at anypoint on the RF transmission line 124 between the output 1008 and thechuck 114. Similarly, in several embodiments, the variable sensor 1022is coupled at any point on the RF transmission line 122 between theoutput 1010 and the edge electrode 1016.

In some embodiments, the system 1000 excludes the RF generator 1002and/or the RF generator 1018. In various embodiments, the system 1000includes any number of RF generators having different frequencies ofoperation, e.g., three, etc., coupled to the IMC 108, and/or any numberof RF generators, e.g., three, etc. having different frequencies ofoperation coupled to the IMC 113.

In several embodiments, the electrode 202 (FIG. 2A) is embedded withinthe edge ring 110 instead of being embedded within the coupling ring 112and is coupled to the RF transmission line 122 in a similar manner asthat described above, e.g., via the RF filter 208 and the power pin 204(FIG. 2A).

In some embodiments, instead of using the edge electrode 1016, the chuck114 is split into two electrodes, e.g., a central lower electrode and aperipheral lower electrode, etc. The central lower electrode is coupledto the RF transmission line 124 and the peripheral lower electrode iscoupled to the RF transmission line 122. The electrode 202 (FIG. 2A) isembedded within the peripheral lower electrode and the electrode 202 iscoupled to the RF transmission line 122 in a similar manner as thatdescribed above, e.g., via the RF filter 208 and the power pin 204 (FIG.2A), etc.

In various embodiments, instead of the edge electrode 1016, the upperelectrode extension 660 (FIG. 6) is coupled to the RF transmission line122 and instead of the chuck 114, the upper electrode 121 (FIG. 6) iscoupled to the RF transmission line 124. In these embodiments, theelectrode 202 (FIG. 2A) is embedded within the upper electrode extension660 and the electrode 202 is coupled to the RF transmission line 122 ina similar manner as that described above, e.g., via the RF filter 208and the power pin 204 (FIG. 2A), etc.

In some embodiments, instead of using the upper electrode extension 660,the upper electrode 121 is split into two electrodes, e.g., a centralupper electrode and a peripheral upper electrode, etc. The central upperelectrode is coupled to the RF transmission line 124 and the peripheralupper electrode is coupled to the RF transmission line 122. Theelectrode 202 (FIG. 2A) is embedded within the peripheral upperelectrode and the electrode 202 is coupled to the RF transmission line122 in a similar manner as that described above, e.g., via the RF filter208 and the power pin 204 (FIG. 2A), etc.

In various embodiments, the master RF generator 1014 has a mediumfrequency of operation among frequencies of operation of RF generatorssupplying power to the chuck 114 and so is a medium frequency (MF)generator. For example, the master RF generator 1014 has a frequency ofoperation of y MHz and the other RF generators supplying power to thechuck 114 has the x MHz frequency and the z MHz frequency. As anotherexample, the master RF generator 1014 has a frequency of operation of yMHz and the other RF generators supplying power to the chuck 114 has thex1 kHz frequency and the z MHz frequency. As another example, the masterRF generator 1014 has a frequency of operation of x MHz and the other RFgenerators supplying power to the chuck 114 has the x1 kHz frequency andthe z MHz frequency. As still another example, the master RF generator1014 has a frequency of operation of x MHz and the other RF generatorssupplying power to the chuck 114 has the x1 kHz frequency and the y MHzfrequency. As yet another example, the frequency of operation of themaster RF generator 104 is between frequencies of operation of other RFgenerators supplying power to the chuck 114.

In various embodiments, the master RF generator 1014 has the highestfrequency of operation among frequencies of operation of RF generatorssupplying power to the chuck 114 and so is a high frequency (HF)generator. For example, the master RF generator 1014 has a frequency ofoperation of z MHz and the other RF generators supplying power to thechuck 114 has the x MHz frequency and the y MHz frequency. As anotherexample, the master RF generator 1014 has a frequency of operation of zMHz and the other RF generators supplying power to the chuck 114 has thex1 kHz frequency and the y MHz frequency. As another example, the masterRF generator 1014 has a frequency of operation of z MHz and the other RFgenerators supplying power to the chuck 114 has the x1 kHz frequency andthe x MHz frequency. As yet another example, the frequency of operationof the master RF generator 104 is greater than frequencies of operationof other RF generators supplying power to the chuck 114.

Similarly, in some embodiments, the slave RF generator 1012 has a mediumfrequency of operation among frequencies of operation of RF generatorssupplying power to the edge electrode 1016 and so is a medium frequencygenerator. For example, the slave RF generator 1012 has a frequency ofoperation of y MHz and the other RF generators supplying power to theedge electrode 1016 has the x MHz frequency and the z MHz frequency. Asanother example, the slave RF generator 1012 has a frequency ofoperation of y MHz and the other RF generators supplying power to theedge electrode 1016 has the x1 kHz frequency and the z MHz frequency. Asanother example, the slave RF generator 1012 has a frequency ofoperation of x MHz and the other RF generators supplying power to theedge electrode 1016 has the x1 kHz frequency and the y MHz frequency. Asstill another example, the slave RF generator 1012 has a frequency ofoperation of x MHz and the other RF generators supplying power to theedge electrode 1016 has the x1 kHz frequency and the z MHz frequency. Asyet another example, the frequency of operation of the slave RFgenerator 1012 is between frequencies of operation of other RFgenerators supplying power to the edge electrode 1016.

In various embodiments, the slave RF generator 1012 has the highestfrequency of operation among frequencies of operation of RF generatorssupplying power to the edge electrode 1016 and so is a high frequencygenerator. For example, the slave RF generator 1012 has a frequency ofoperation of z MHz and the other RF generators supplying power to theedge electrode 1016 has the x MHz frequency and the y MHz frequency. Asanother example, the slave RF generator 1012 has a frequency ofoperation of z MHz and the other RF generators supplying power to theedge electrode 1016 has the x1 kHz frequency and the y MHz frequency. Asanother example, the slave RF generator 1012 has a frequency ofoperation of z MHz and the other RF generators supplying power to theedge electrode 1016 has the x1 kHz frequency and the x MHz frequency. Asyet another example, the frequency of operation of the slave RFgenerator 1012 is greater than frequencies of operation of other RFgenerators supplying power to the edge electrode 1016.

In some embodiments, the phases of the variables associated with theoutputs 1008 and 1010 are adjusted before the frequency of operation ofthe slave RF generator 1012 is adjusted to be within the pre-determinedrange from the frequency of operation of the master RF generator 1014.In various embodiments, the phases of the variables associated with theoutputs 1008 and 1010 are adjusted simultaneously with, e.g., at thesame time, during the same clock cycle, etc., the frequency of operationof the slave RF generator 1012 is adjusted to be within thepre-determined range from the frequency of operation of the master RFgenerator 1014.

FIG. 11 is a diagram of an embodiment of a system 1100 to illustratefrequency locking and phase locking between a master RF generator 1014Aand a slave RF generator 1012A when both the master RF generator 1014Aand the slave RF generator 1012A are operating in a continuous waveformmode. The master RF generator 1014A is an example of the master RFgenerator 1014 (FIG. 10) and the slave RF generator 1012A is an exampleof the slave RF generator 1012 (FIG. 10). As an example, in thecontinuous waveform mode, an RF generator generates an RF signal thathas a power level, e.g., a maximum amplitude of the RF signal, a rootmean square value of magnitudes of the RF signal, an envelope of the RFsignal, etc., within a pre-defined range of two power levels. The RFsignal in the continuous waveform mode has one state, e.g., state S1 orstate S2, etc., and does not have multiple states, which are furtherdescribed below.

The system 1100 includes the master RF generator 1014A, the slave RFgenerator 1012A, the IMC 108, the IMC 113, and the host computer system306. The master RF generator 1014A includes a digital signal processor(DSP) 1102, a driver 1104, and an RF power supply 1106. An RF powersupply, described herein, is a power source. The DSP 1102 is coupled tothe driver 1104 via a conductor, e.g., a wire, a cable, etc., and thedriver 1104 is coupled to the RF power supply 1106 via a conductor. Thehost computer system 306 is coupled to the DSP 1102 via a transfer cable1108. Examples of a driver include one or more transistors.

The slave RF generator 1012A includes a DSP 1114, a driver 1116, and anRF power supply 1118. The DSP 1114 is coupled to the driver 1116 via aconductor and the driver 1114 is coupled to the RF power supply 1118 viaa conductor. The host computer system 306 is coupled to the DSP 1114 viaa transfer cable 1110.

The DSP 1102 receives from the host computer system 306 via the transfercable 1108 a frequency and power of the RF signal to be generated by themaster RF generator 1014A. The DSP 1102 sends a control signal to thedriver 1104 to indicate the power and frequency of the RF signal. Thedriver 1104 drives, e.g., generates, etc., a drive signal, e.g., acurrent signal, etc., based on the, e.g., having the, etc., power andfrequency received from the control signal and provides the currentsignal to the RF power supply 1106. The RF power supply 1106 generatesthe RF signal that is provided via the RF cable 1036 to input 1040 ofthe IMC 108. The RF signal has the frequency and the power received fromthe control signal.

The DSP 1102 provides the frequency of the RF signal generated by theDSP 1102 via the transfer cable 1050 to the DSP 1114 of the slave RFgenerator 1012A. The DSP 1114 of the slave RF generator 1102 receivesthe frequency from the DSP 1102 and determines to generate a controlsignal indicating a frequency that is within the pre-determined rangefrom the frequency received from the DSP 1102. Furthermore, the DSP 1114receives from the processor of the host computer system 306 via thetransfer cable 1110, a power of the RF signal to be generated by theslave RF generator 1012A. The DSP 1114 sends a control signal to thedriver 1116 to indicate the power, received from the host computersystem 306, and the frequency, within the pre-determined range, of theRF signal. The driver 1116 drives, e.g., generates, etc., a drivesignal, e.g., a current signal, etc., based on the, e.g., having the,etc., power and frequency received from the control signal and providesthe current signal to the RF power supply 1118. The RF power supply 1118generates the RF signal having the power, received from the hostcomputer system 306, and the frequency, received from the DSP 1114. TheRF signal is supplied by the RF power supply 1118 via the RF cable 1046to the IMC 113 to generate the modified signal that is transferred viathe RF transmission line 122.

Moreover, once the modified RF signal is supplied via the RFtransmission line 122 is generated based on the RF signal generated bythe slave RF generator 1012A, the DSP 1114 receives the variableassociated with the output 1008 via the transfer cable 1030 and thevariable associated the output 1010 via the transfer cable 1032. Thevariable associated with the output 1008 includes a phase of thevariable associated with the output 1008 and the variable associated theoutput 1010 includes a phase of the variable associated with the output1008. The DSP 1114 compares the phase of the variable associated withthe output 1010 with the phase of the variable associated with theoutput 1008 to determine whether the phases are within the pre-set rangefrom each other. Upon determining that the phases are not within thepre-set range from each other, the DSP 1114 determines a phase of the RFsignal to be modified by the slave RF generator 1012A so that the phaseof the variable associated with the output 1010 is within the pre-setrange from the phase of the variable associated with the output 1008.For example, the DSP 1114 determines a time, e.g., a clock cycle, etc.,at which the RF signal is to be output by the slave RF generator 1012Aso that the phase of the RF signal is within the pre-set range from thephase of the variable associated with the output 1008. The DSP 1114indicates the phase of the RF signal to be modified by the slave RFgenerator 1012A within the control signal sent to the driver 1116. Forexample, the DSP 1114 determines to send the control signal at the timeto the driver 1116 so that the phase of the variable associated with theoutput 1010 is within the pre-set range from the phase of the variableassociated with the output 1008.

Moreover, once the DSP 1114 determines the frequency that is within thepre-determined range from the frequency received from the DSP 1102 andthe phase of the RF signal that is within the pre-set range, the DSP1114 determines a magnitude of the variable of the RF signal to achievethe factor. For example, after determining the frequency that is withinthe pre-determined range from the frequency received from the DSP 1102and the phase of the RF signal that is within the pre-set range, the DSP1114 accesses from a table 1200 (see FIG. 12) stored in the memorydevice 1112 a magnitude of the variable, e.g., complex power, complexvoltage, etc., of the RF signal to be modified by the slave RF generator1012A and indicates the magnitude within the control signal to be sentto the driver 1116. The DSP 1114 determines the magnitude of thevariable that corresponds to, e.g., has a one-to-one relationship with,is linked to, is mapped to, etc., a value of the factor.

At the time, the DSP 1114 sends the control signal indicating thefrequency that is within the pre-determined range from the frequencyreceived from the DSP 1102 and the magnitude of the variable of the RFsignal to be modified by the slave RF generator 1012A to the driver1116. Furthermore, at the time, the driver 1116 generates a drive signalbased on, e.g., having, etc., the frequency received from the DSP 114and the magnitude of the variable indicated within the control signalreceived from the DSP 1114 and provides the drive signal to the RF powersupply 1118. Furthermore, at the time, the RF power supply 1118generates the RF signal having the frequency, within the pre-determinedrange, and the magnitude, determined based on the factor, upon receivingthe drive signal from the driver 1116, and sends the RF signal via theRF cable 1046 to the input 1042 of the IMC 113.

In some embodiments, a phase-locked loop (PLL), e.g., a phase detectorcoupled to an oscillator, etc., is associated with the outputs 1008 and1010 to determine a phase difference between the modified RF signalsthat are transferred via the RF transmission lines 122 and 124. Forexample, inputs of the phase detector are coupled to the output 1008 andthe output 1010. As another example, an input of the phase detector iscoupled to any point on the RF transmission line 122 and another inputof the phase detector is coupled to any point on the RF transmissionline 124. An output of the phase detector is coupled to the oscillatorof the PLL and an output of the oscillator of the PLL is coupled to theDSP 1114. The phase detector of the PLL determines a difference betweenphases of the modified RF signal passing through the RF transmissionline 122 and the modified RF signal passing through the RF transmissionline 124, and sends a signal to the oscillator of the PLL so that theoscillator of the PLL generates a signal to achieve the pre-set rangebetween phases of the variable associated with the output 1008 and thevariable associated with the output 1010. The signal generated by theoscillator is provided to the DSP 114 that determines a phase of thesignal.

In some embodiments, a driver of an RF generator is a part of an RFpower supply of the RF generator. For example, the driver 1104 is a partof the RF power supply 1106. As another example, the driver 1116 is apart of the RF power supply 1118.

FIG. 12 is a diagram of an embodiment of the table 1200 to illustrate acorrespondence between the factor and the variable of the RF signal thatis to be modified by the slave RF generator 1012A (FIG. 11). The table1200 includes a correspondence between various values, e.g., FTR1, FTR2,FTR3, etc., of the factor and values, e.g., VR1, VR2, VR3, etc. of thevariable of the RF signal to be modified by the slave RF generator1012A. For example, the value FTR1 corresponds to, e.g., is uniquelyassociated with, etc., the value VR1, the value FTR2 corresponds to thevalue VR2, and the value FTR3 is corresponds to the value VR3. Each ofthe values VR1, VR2, and VR3 is a magnitude of the variable, e.g.,complex power, complex voltage, complex current, etc., of the RF signalto be modified by the RF power supply 1118.

FIG. 13 is a diagram of an embodiment of a system 1300 to illustratefrequency locking and phase locking between a master RF generator 1014Band a slave RF generator 1012B when both the master RF generator 1014Band the slave RF generator 1012B are operating in a state transitionmode. In the state transition mode, each RF generator transitionsbetween multiple states, e.g., between the state S1 and the state S2,among three states S1, S2, and S3, among any other number of states,etc. During the state S1, each RF generator generates an RF signal thathas a power level that is outside the pre-defined range from a powerlevel of the RF signal during the state S2. The master RF generator1014B is an example of the master RF generator 1014 (FIG. 10) and theslave RF generator 1012B is an example of the slave RF generator 1012(FIG. 10).

The master RF generator 1014B includes the DSP 1102, a power controller1302 for the state S1, a power controller 1304 for the state S2, an autofrequency tuner (AFT) 1306 for the state S1, and an AFT 1308 for thestate S2. The DSP 1102 is coupled to the power controllers 1302 and1304, and to the AFTs 1306 and 1308. Moreover, the power controllers1302 and 1304, and the AFTs 1306 and 1308 are coupled to the driver1104.

Similarly, the slave RF generator 1012B includes the DSP 1114, a powercontroller 1310 for the state S1, a power controller 1312 for the stateS2, an AFT 1314 for the state S1, and an AFT 1316 for the state S2. TheDSP 1114 is coupled to the power controllers 1310 and 1312, and to theAFTs 1314 and 1316. Moreover, the power controllers 1310 and 1312, andthe AFTs 1314 and 1316 are coupled to the driver 1116.

The DSP 1102 receives a transistor-transistor logic (TTL) signal, e.g.,a clock signal, etc., via the transfer cable 1108 from a clock source,e.g., a clock source, a digital oscillator, a digital pulse generator,the processor, etc., of the host computer system 306 and the DSP 1114receives the TTL signal via the transfer cable 1110 from the clocksource of the host computer system 306. The TTL signal transitionsbetween the states S1 and S2, e.g., logic levels high and low, or logiclevels 0 and 1, etc.

The DSP 1102 receives the TTL signal and distinguishes between the stateS1 and S2 of the TTL signal. The DSP 1102 also receives a power levelfor the state S1, a power level for the state S2, a frequency for thestate S1, and a frequency for the state S2 from the processor of thehost computer system 306 via the transfer cable 1108. As an example, afrequency of an RF signal generated by an RF generator during the stateS1 is different from a frequency of the RF signal generated by the RFgenerator during the state S2. As another example, a frequency of an RFsignal generated by an RF generator during the state S1 is the same asthe frequency of the RF signal generated by the RF generator during thestate S2. When the TTL signal is in the state S1, the DSP 1102 sends asignal to the power controller 1302 indicating a power level of an RFsignal to be generated by the master RF generator 1014B and a signal tothe AFT 1306 indicating a frequency of the RF signal to be generated bythe master RF generator 1014B. The power controller 1302 sends a controlsignal to the driver 1104 indicating the power level received from theDSP 1102 and the AFT 1306 sends a control signal to the driver 1104indicating the frequency received from the DSP 1102.

The driver 1104 generates a drive signal, e.g., a current signal, etc.,having the frequency for the state S1 and the power level for the stateS1, and provides the drive signal to the RF power supply 1104. Uponreceiving the drive signal during the state S1, the RF power supply 1106generates the RF signal having the frequency for the state S1 and thepower level for the state S1.

Similarly, when the TTL signal is in the state S2, the DSP 1102 sends asignal to the power controller 1304 indicating a power level of the RFsignal to be generated by the master RF generator 1014B and a signal tothe AFT 1308 indicating a frequency of the RF signal to be generated bythe master RF generator 1014B. The power controller 1304 sends a controlsignal to the driver 1104 indicating the power level received from theDSP 1102 and the AFT 1308 sends a control signal to the driver 1104indicating the frequency received from the DSP 1102.

The driver 1104 generates a drive signal having the frequency for thestate S2 and the power level for the state S2, and provides the drivesignal to the RF power supply 1104. Upon receiving the drive signalduring the state S2, the RF power supply 1106 generates the RF signalhaving the frequency for the state S2 and the power level for the stateS2.

During the state S1, the DSP 1102 provides the frequency, for the stateS1, of the RF signal generated by the DSP 1102 via the transfer cable1050 to the DSP 1114 of the slave RF generator 1012B. The DSP 1114 ofthe slave RF generator 1102 receives the frequency, for the state S1,from the DSP 1102 and determines to generate a signal indicating afrequency, for the state S1, that is within a pre-determined range, forthe state S1, from the frequency received from the DSP 1102 for thestate S1. The signal indicating the frequency, for the state S1, that iswithin the pre-determined range is provided from the DSP 1114 to the AFT1314.

Also, the DSP 1114 receives the TTL signal and distinguishes between thestate S1 and S2 of the TTL signal. The DSP 1114 also receives a powerlevel for the state S1, and a power level for the state S2 from theprocessor of the host computer system 306 via the transfer cable 1110.When the TTL signal is in the state S1, the DSP 1114 sends a signal tothe power controller 1310 indicating a power level of an RF signal to begenerated by the slave RF generator 1012B and a signal to the AFT 1314indicating the frequency of the RF signal to be generated by the slaveRF generator 1012B. The frequency, for the state S1, of the RF signal tobe generated is within the pre-determined range of the frequency, forthe state S1, received from the DSP 1102. The power controller 1310sends a control signal to the driver 1116 indicating the power levelreceived from the DSP 1114 and the AFT 1314 sends a control signal tothe driver 1116 indicating the frequency received from the DSP 1114.

The driver 1116 generates a drive signal, e.g., a current signal, etc.,based on, e.g., having, etc., the frequency, received from the DSP 1102,for the state S1, and the power level, for the state S1, and providesthe drive signal to the RF power supply 1118. Upon receiving the drivesignal during the state S1, the RF power supply 1118 generates the RFsignal having the frequency for the state S1 and the power level for thestate S1.

Moreover, during the state S1, once the modified RF signal that is sentvia the RF transmission line 122 is generated based on the RF signalthat is generated by the slave RF generator 1012B, the DSP 1114 receivesthe variable, for the state S1, associated with the output 1008 via thetransfer cable 1030 and the variable, for the state S1, associated theoutput 1010 via the transfer cable 1032. The variable, for the state S1,associated with the output 1008 for the state S1 includes a phase of thevariable associated with the output 1008 and the variable, for the stateS1, associated the output 1010 includes a phase of the variableassociated with the output 1008. During the state S1, the DSP 1114compares the phase of the variable, for the state S1, associated withthe output 1010 with the phase of the variable, for the state S1,associated with the output 1008 to determine whether the phases arewithin a pre-set range from each other for the state S1. Moreover,during the state S1, upon determining that the phases, for the state S1,are not within the pre-set range, for the state S1, from each other, theDSP 1114 determines a phase, for the state S1, of the RF signal to bemodified by the slave RF generator 1012B so that the phase, for thestate S1, of the variable associated with the output 1010 is within thepre-set range for the state S1 from the phase, for the state S1, of thevariable associated with the output 1008. For example, the DSP 1114determines a time, e.g., a clock cycle, etc., at which the RF signal isto be output by the slave RF generator 1012B so that the phase of the RFsignal, for the state S1, is within the pre-set range, for the state S1,from the phase, for the state S1, of the variable associated with theoutput 1008. During the state S1, the DSP 1114 sends a signal at thetime to the AFT 1314 and to the power controller 1310. Upon receivingthe signal at the time from the DSP 1114, the AFT 1314 generates andsends a control signal indicating the frequency, for the state S1,received from the DSP 1114 to the driver 1116. The frequency receivedfrom the DSP 1114 by the AFT 1314 is within the pre-determined range forthe state S1 from the frequency received from the DSP 1102 for the stateS1.

Moreover, during the state S1, once the DSP 1114 determines thefrequency, for the state S1, that is within the pre-determined range,for the state S1, from the frequency, for the state S1, received fromthe DSP 1102 and the phase, for the state S1, of the RF signal to bemodified by the slave RF generator 1012B, the DSP 1114 determines amagnitude, for the state S1, of the variable of the RF signal to achievethe factor for the state S1. For example, after determining thefrequency, for the state S1, that is within the pre-determined range,for the state S1, from the frequency, for the state S1, received fromthe DSP 1102 and the phase, for the state S1, of the RF signal to bemodified by the slave RF generator 1012B, the DSP 1114 accesses from atable 1500 (see FIG. 15) stored in the memory device 1112 a magnitude,for the state S1, of the variable, e.g., complex power, complex voltage,etc., of the RF signal to be modified by the slave RF generator 1012Band indicates the magnitude within a signal. The DSP 1114 sends thesignal indicating the magnitude of the variable to the power controller1310 at the time to the power controller 1310, and upon receiving thesignal, the power controller 1310 generates a control signal indicatingthe magnitude, for the state S1, and sends the control signal to thedriver 1116.

During the state S1, the driver 1116 generates, at the time, for thestate S1, a drive signal having the frequency for the state S1 indicatedwithin the signal received from the AFT 1314 and having the magnitude ofthe variable for the state S1 received from the power controller 1310,and provides the drive signal to the RF power supply 1118. During thestate S1, upon receiving the drive signal from the driver 1116, the RFpower supply 1118 generates, at the time, the RF signal having thefrequency for the state S1 and the magnitude of the variable for thestate S1, and sends the RF signal via the RF cable 1046 to the input1042 of the IMC 113.

Moreover, during the state S2, the DSP 1102 provides the frequency, forthe state S2, of the RF signal generated by the DSP 1102 via thetransfer cable 1050 to the DSP 1114 of the slave RF generator 1012B. Asan example, the frequency for the state S2 is different from, e.g., lessthan, greater than, etc., the frequency for the state S1. As anotherexample, the frequency for the state S2 is the same as the frequency forthe state S1. The DSP 1114 of the slave RF generator 1102 receives thefrequency, for the state S2, from the DSP 1102 and determines togenerate a signal indicating a frequency, for the state S2, that iswithin a pre-determined range for the state S2 from the frequencyreceived from the DSP 1102 for the state S2. It should be noted that asan example, the pre-determined range for the state S2 is different from,e.g., less than, greater than, etc., the pre-determined range for thestate S1. As another example, the pre-determined range for the state S2is the same as the pre-determined range for the state S1.

When the TTL signal is in the state S2, the DSP 1114 sends a signal tothe power controller 1312 indicating the power level, received from thehost computer system 306, of the RF signal to be generated by the slaveRF generator 1012B and a signal to the AFT 1316 indicating thefrequency, for the state S2, of the RF signal to be generated by theslave RF generator 1012B. The frequency, for the state S2, is within thepre-determined range for the state S2 from the frequency received fromthe DSP 1102 for the state S2. The power controller 1312 sends a controlsignal to the driver 1116 indicating the power level received from theDSP 1114 and the AFT 1316 sends a control signal to the driver 1116indicating the frequency received from the DSP 1114.

The driver 1116 generates a drive signal having the frequency for thestate S2 and the power level for the state S2, and provides the drivesignal to the RF power supply 1118. Upon receiving the drive signalduring the state S2, the RF power supply 1118 generates the RF signalhaving the frequency for the state S2 and the power level for the stateS2.

Moreover, once the modified RF signal transferred via the RFtransmission line 124 is generated based on the RF signal, having thefrequency, within the pre-determined range, for the state S2 generatedby the slave RF generator 1012B, the DSP 1114 receives the variable, forthe state S2, associated with the output 1008 via the transfer cable1030 and the variable, for the state S2, associated the output 1010 viathe transfer cable 1032. The variable, for the state S2, associated withthe output 1008 includes a phase of the variable associated with theoutput 1008 and the variable, for the state S2, associated the output1010 includes a phase of the variable associated with the output 1008.As an example, the phase of the variable associated with the output 1008for the state S2 is different from, e.g., less than, greater than, etc.,the phase of the variable associated with the output 1008 for the stateS1. As another example, the phase of the variable associated with theoutput 1008 for the state S2 is the same as the phase of the variableassociated with the output 1008 for the state S1. As an example, thephase of the variable associated with the output 1010 for the state S2is different from, e.g., less than, greater than, etc., the phase of thevariable associated with the output 1010 for the state S1. As anotherexample, the phase of the variable associated with the output 1010 forthe state S2 is the same as the phase of the variable associated withthe output 1010 for the state S1.

During the state S2, the DSP 1114 compares the phase of the variable,for the state S2, associated with the output 1010 with the phase of thevariable, for the state S2, associated with the output 1008 to determinewhether the phases are within a pre-set range from each other for thestate S2. It should be noted that as an example, the pre-set range forthe state S2 is different from, e.g., less than, greater than, etc., thepre-set range for the state S1. As another example, the pre-set rangefor the state S2 is the same as the pre-set range for the state S1.Moreover, during the state S2, upon determining that the phases, for thestate S2, are not within the pre-set range, for the state S2, from eachother, the DSP 1114 determines a phase, for the state S2, of the RFsignal generated by the slave RF generator 1012B so that the phase, forthe state S2, of the variable associated with the output 1010 is withinthe pre-set range, for the state S2, from the phase, for the state S2,of the variable associated with the output 1008. For example, the DSP1114 determines a time, e.g., a clock cycle, etc., at which the RFsignal is to be output by the slave RF generator 1012B so that the phaseof the RF signal, for the state S2, is within the pre-set range, for thestate S2, from the phase, for the state S2, of the variable associatedwith the output 1008. During the state S2, the DSP 1114 sends a signalat the time, for the state S2, to the AFT 1316 and to the powercontroller 1312. Upon receiving the signal at the time from the DSP1114, the AFT 1316 generates and sends a control signal indicating thefrequency, for the state S2, received from the DSP 1114 to the driver1116. The frequency received from the DSP 1114 by the AFT 1316 is withinthe pre-determined range, for the state S2, from the frequency receivedfrom the DSP 1102 for the state S2.

Moreover, during the state S2, once the DSP 1114 determines thefrequency, for the state S2, that is within the pre-determined range,for the state S2, from the frequency, for the state S2, received fromthe DSP 1102 and the phase, for the state S2, that is within the pre-setrange, for the state S2, of the RF signal to be modified by the slave RFgenerator 1012B, the DSP 1114 determines a magnitude, for the state S2,of the variable of the RF signal to achieve the factor for the state S2.For example, after determining the frequency, for the state S2, that iswithin the pre-determined range, for the state S2, from the frequency,for the state S2, received from the DSP 1102 and the phase, for thestate S2, of the RF signal to be modified by the slave RF generator1012B, the DSP 1114 accesses from the table 1500 stored in the memorydevice 1112 a magnitude, for the state S2, of the variable, e.g.,complex power, complex voltage, etc., of the RF signal to be modified bythe slave RF generator 1012B and indicates the magnitude within asignal. The DSP 1114 sends the signal to the power controller 1312 atthe time to the power controller 1312, and upon receiving the signal,the power controller 1312 generates a control signal indicating themagnitude, for the state S2, and sends the control signal to the driver1116.

The driver 1116 generates, at the time for the state S2, a drive signalhaving the frequency for the state S2 indicated within the signalreceived from the AFT 1316 and having the magnitude of the variable forthe state S2 received from the power controller 1312, and provides thedrive signal to the RF power supply 1118. During the state S2, uponreceiving the drive signal from the driver 1116, the RF power supply1118 generates, at the time for the state S2, the RF signal having thefrequency for the state S2 and the magnitude for the state S2, and sendsthe RF signal via the RF cable 1046 to input 1042 of the IMC 113.

In some embodiments, the PLL is associated with the outputs 1008 and1010 to determine, during the state S1, a phase difference between themodified RF signals that are transferred via the RF transmission lines122 and 124. During the state S1, the phase detector of the PLLdetermines a difference between phases of the modified RF signal passingthrough the RF transmission line 122 and the modified RF signal passingthrough the RF transmission line 124, and sends a signal to theoscillator of the PLL so that the oscillator generates a signal toachieve the pre-set range, for the state S1, between phases of thevariable associated with the output 1008 and the variable associatedwith the output 1010. The signal generated by the oscillator isprovided, during the state S1, to the DSP 114 that determines a phase ofthe signal.

Similarly, in various embodiments, the PLL is associated with theoutputs 1008 and 1010 to determine, during the state S2, a phasedifference between the modified RF signals that are transferred via theRF transmission lines 122 and 124. As an example, the phase differencebetween the modified signals that are transferred via the RFtransmission lines 122 and 124 during the state S2 is different from,e.g., less than, greater than, etc., the phase difference between themodified signals during the state S1. As another example, the phasedifference between the modified signals that are transferred via the RFtransmission lines 122 and 124 during the state S2 is the same as thephase difference between the modified signals during the state S1.Moreover, during the state S2, the phase detector of the PLL determinesa difference between phases of the modified RF signal passing throughthe RF transmission line 122 and the modified RF signal passing throughthe RF transmission line 124, and sends a signal to the oscillator ofthe PLL so that the oscillator generates a signal to achieve the pre-setrange, for the state S2, between phases of the variable associated withthe output 1008 and the variable associated with the output 1010. Thesignal generated by the oscillator is provided, during the state S2, tothe DSP 114 that determines a phase of the signal.

In some embodiments, instead of the TTL signal being supplied from thehost computer system 306 to the slave RF generator 1012B, the TTL signalis received by the DSP 1102 from the clock source of the host system306, and the DSP 1102 sends the TTL signal via the transfer cable 1050to the DSP 1114 to synchronize operation of the slave RF generator 1012Bwith that of the master RF generator 1014B.

FIG. 14 is a diagram of an embodiment of a timing diagram to illustratemultiple states of an RF signal 1402 generated by the master RFgenerator 1014B (FIG. 13), of an RF signal generated by the slave RFgenerator 1012B (FIG. 13), and of a TTL signal 1406. A graph 1408 plotslogic levels, e.g., 0 and 1, low and high, etc., of the TTL signal 1404versus time t. One logic level corresponds to the state S1 and anotherlogic level corresponds to the state S2. Moreover, a graph 1410 plotspower levels of the RF signal 1402 generated by the master RF generator1014B for the states S1 and S2 versus the time t, and the graph 1412plots power levels of the RF signal 1404 generated by the slave RFgenerator 1012B for the states S1 and S2 versus the time t.

As shown in the graph 1410, a power level of the RF signal 1402 duringthe state S1 is P1, and power level of the RF signal 1402 is 0 duringthe state S2. Moreover, as shown in the graph 1412, a power level of theRF signal 1404 is P2 during the state S1, and a power level of the RFsignal 1404 is 0 during the state S2. As an example, the power level P1is equal to the power level P2. As another example, the power level P1is different from e.g., greater than, less than, etc., the power levelP2. Each of the RF signal 1402 and the RF signal 1404 transitions in aperiodic manner between the states S1 and S2 synchronous with the TTLsignal 1408. For example, during a half duty cycle of the TTL signal1408, the RF signal 1402 has the power level P1 and during the remaininghalf duty cycle of the TTL signal 1408, the RF signal 1402 has the powerlevel zero. As another example, during a half duty cycle of the TTLsignal 1408, the RF signal 1404 has the power level P2 and during theremaining half duty cycle of the TTL signal 1408, the RF signal 1404 hasthe power level zero. Other examples of the duty cycle include a 40%duty cycle, a 30% duty cycle, a 70% duty cycle, a 60% duty cycle, etc.

In various embodiments, the frequency of the RF signal 1402 during thestate S1 is different from, e.g., less than, greater than, etc., thefrequency of the RF signal 1404 during the state S1. As another example,the frequency of the RF signal 1402 during the state S1 is the same asthe frequency of the RF signal 1404 during the state S1.

In several embodiments, the frequency of the RF signal 1402 during thestate S2 is different from, e.g., less than, greater than, etc., thefrequency of the RF signal 1404 during the state S2. As another example,the frequency of the RF signal 1402 during the state S2 is the same asthe frequency of the RF signal 1404 during the state S2.

In some embodiments, a power level of the RF signal 1402 is P1 duringthe state S1, and a power level of the RF signal 1402 is P3 during thestate S2, where P3 is less than P1 and is greater than zero. In variousembodiments, a power level of the RF signal 1404 is P2 during the stateS1, and a power level of the RF signal 1404 is P4 during the state S2,where P4 is less than P2 and is greater than zero.

FIG. 15 is a diagram of an embodiment of the table 1500 to illustrate acorrespondence between the values of factor for the states S1 and S2 andmagnitudes of the variable of the RF signal that is to be modified bythe slave RF generator 1012B (FIG. 13) for the states S1 and S2. Thetable 1500 includes a correspondence between various values, e.g.,FTRS11, FTRS12, etc., of the factor, for the state S1, and values, e.g.,VRS11, VRS12, etc. of the variable, for the state S1, of the RF signalto be modified by the slave RF generator 1012B during the state S1. Forexample, for the state S1, the value FTRS11 corresponds to, e.g., isuniquely associated with, is mapped to, is linked to, etc., the valueVRS11 and the value FTRS12 corresponds to the value VRS12. Each of thevalues VRS11 and VRS12 is a magnitude of the variable, e.g., complexpower, complex voltage, complex current, etc., of the RF signal to bemodified by the RF power supply 1118 during the state S1.

Moreover, the table 1500 includes a correspondence between variousvalues, e.g., FTRS21, FTRS22, etc., of the factor during the state S2and values, e.g., VRS21, VRS22, etc. of the variable, for the state S2,of the RF signal to be modified by the slave RF generator 1012B duringthe state S2. For example, for the state S2, the value FTRS21corresponds to the value VRS21 and the value FTRS22 corresponds to thevalue VRS22. Each of the values VRS21 and VRS22 is a magnitude of thevariable, e.g., complex power, complex voltage, complex current, etc.,of the RF signal to be modified by the RF power supply 1118 during thestate S2.

FIG. 16A is a diagram of an embodiment of a graph 1600 to illustrate adifference in phases, e.g., a phase shift, etc., of the variableassociated with the output 1008 (FIG. 10) and the variable associatedwith the output 1010 (FIG. 10). The graph 1600 plots voltage V versusthe time t. The graph 1600 includes a plot 1602 of a voltage waveformmeasured by the variable sensor 1020 (FIG. 10) and a plot 1604 of avoltage waveform measured by the variable sensor 1022 (FIG. 10). Beforethe phases of the variables associated with the outputs 1008 and 1010are adjusted by the slave RF generator 1012 (FIG. 10), the phase shiftexists between the voltage waveforms 1602 and 1604.

FIG. 16B is a diagram of an embodiment of a graph 1606 to illustrate areduction in the difference in phases of the variable associated withthe output 1008 (FIG. 10) and the variable associated with the output1010 (FIG. 10). The graph 1606 plots the voltage V versus the time t.The graph 1606 includes the plot 1602 of the voltage waveform measuredby the variable sensor 1020 (FIG. 10) and the plot 1604 of the voltagewaveform measured by the variable sensor 1022 (FIG. 10). After thephases of the variables associated with the outputs 1008 and 1010 areadjusted by the slave RF generator 1012 (FIG. 10), the phase shiftbetween the voltage waveforms 1602 and 1604 is reduced, e.g., isnonexistent, is reduced to zero, is reduce to be within the pre-setrange, etc.

FIG. 16C is a diagram of an embodiment of a graph 1608 to illustrate achange, e.g., increase, decrease, etc., in a magnitude of the voltagewaveform 1604 to achieve the factor. The graph 1608 plots voltage versustime. The change in the magnitude of the voltage waveform 1604 isachieved when the change in the magnitude of the variable of the RFsignal generated by the slave RF generator 1012 is achieved.

FIG. 17A is a diagram of an embodiment of a graph 1700 to illustratethat, during a process 1, a tilt of the plasma sheath in the edge region102 (FIG. 10) is controlled by controlling the magnitude of the variableof the RF signal generated by the slave RF generator 1012. Moreover,there is little or no effect on the plasma sheath within the centerregion 132 (FIG. 10) when the magnitude of the variable of the RF signalgenerated by the slave RF generator 1012 is changed to achieve thefactor. Such little or no effect is achieved when the phase of the RFsignal generated by the slave RF generator 1012 (FIG. 10) is within thepre-set range from the phase of the RF signal generated by the master RFgenerator 1014 (FIG. 10) and/or frequency of the RF signal generated bythe slave RF generator 1012 is within the pre-determined range from thefrequency of the RF signal generated by the master RF generator 1014.The graph 1700 includes a plot 1702, a plot 1704, and a plot 1706, andplots tilt angle, measured in degrees, versus a radius, measured inmillimeters (mm), of the substrate 120 (FIG. 10). As shown, when a firstamount of power magnitude is applied by the slave RF generator 1012 tothe edge electrode 1016, there is an outward tilt of the plasma sheathin the edge region 102. Moreover, when a second amount of powermagnitude is applied by the slave RF generator 1012 to the edgeelectrode 1016, the outward tilt of the plasma sheath in the edge region102 is reduced to a substantially flat tilt of the plasma sheath in theedge region 102. Also, when a third amount of power magnitude is appliedby the slave RF generator 1012 to the edge electrode 1016, thesubstantially flat tilt is changed into an inward tilt of the plasmasheath in the edge region 102. The first power magnitude is greater thanthe second power magnitude, which is greater than the third powermagnitude.

FIG. 17B is a diagram of an embodiment of a graph 1708 to illustratethat, during a process 2, a tilt of the plasma sheath in the edge region102 (FIG. 10) is controlled by controlling the magnitude of the variableof the RF signal generated by the slave RF generator 1012. The graph1708 includes a plot 1710, a plot 1712, and a plot 1714, and plots tiltangle versus a radius of the substrate 120 (FIG. 10). As shown, when afourth amount of power magnitude is applied by the slave RF generator1012 to the edge electrode 1016, there is an outward tilt of the plasmasheath in the edge region 102. Moreover, when a fifth amount of powermagnitude is applied by the slave RF generator 1012 to the edgeelectrode 1016, the outward tilt of the plasma sheath in the edge region102 is reduced. Also, when a sixth amount of power magnitude is appliedby the slave RF generator 1012 to the edge electrode 1016, the tiltshown in the plot 1712 is changed into an inward tilt of the plasmasheath in the edge region 102. The fourth power magnitude is greaterthan the fifth power magnitude, which is greater than the sixth powermagnitude.

In some embodiments, at least a portion of the recipe, e.g., a pressurewithin the plasma chamber 104 (FIG. 1), or a temperature within theplasma chamber 104, or a gap between the upper electrode 121 (FIG. 1)and the chuck 114 (FIG. 1), or a type of process gas, or an amount ofthe process gas, or a flow rate of the process gas, or a height of theedge electrode 1016 (FIG. 10), or a material of the edge electrode 1016,or a rate of exit of plasma from the plasma chamber 104, or acombination of two or more thereof, etc., for the process 2 is differentthan the portion of the recipe during the process 1.

It should be noted that in some of the above-described embodiments, anRF signal is supplied to the chuck 114 and the upper electrode 121 isgrounded. In various embodiments, an RF signal is applied to the upperelectrode 121 and the chuck 114 is grounded.

In some embodiments, each of the electrode 202 and the coupling ring 112are segmented into a plurality of segments. Each of the segments of theelectrode 202 is independently provided RF power from one or more RFgenerators.

Embodiments, described herein, may be practiced with various computersystem configurations including hand-held hardware units, microprocessorsystems, microprocessor-based or programmable consumer electronics,minicomputers, mainframe computers and the like. The embodiments,described herein, can also be practiced in distributed computingenvironments where tasks are performed by remote processing hardwareunits that are linked through a computer network.

In some embodiments, a controller is part of a system, which may be partof the above-described examples. The system includes semiconductorprocessing equipment, including a processing tool or tools, chamber orchambers, a platform or platforms for processing, and/or specificprocessing components (a wafer pedestal, a gas flow system, etc.). Thesystem is integrated with electronics for controlling its operationbefore, during, and after processing of a semiconductor wafer orsubstrate. The electronics is referred to as the “controller,” which maycontrol various components or subparts of the system. The controller,depending on processing requirements and/or a type of the system, isprogrammed to control any process disclosed herein, including a deliveryof process gases, temperature settings (e.g., heating and/or cooling),pressure settings, vacuum settings, power settings, RF generatorsettings, RF matching circuit settings, frequency settings, flow ratesettings, fluid delivery settings, positional and operation settings,wafer transfers into and out of a tool and other transfer tools and/orload locks connected to or interfaced with the system.

Broadly speaking, in a variety of embodiments, the controller is definedas electronics having various integrated circuits, logic, memory, and/orsoftware that receive instructions, issue instructions, controloperation, enable cleaning operations, enable endpoint measurements, andthe like. The integrated circuits include chips in the form of firmwarethat store program instructions, digital signal processors (DSPs), chipsdefined as Application Specific Integrated Circuit (ASICs), programmablelogic devices (PLDs), one or more microprocessors, or microcontrollersthat execute program instructions (e.g., software). The programinstructions are instructions communicated to the controller in the formof various individual settings (or program files), defining operationalparameters for carrying out a process on or for a semiconductor wafer.The operational parameters are, in some embodiments, a part of a recipedefined by process engineers to accomplish one or more processing stepsduring the fabrication of one or more layers, materials, metals, oxides,silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some embodiments, is a part of or coupled to acomputer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller is in a “cloud” or all or a part of a fab host computersystem, which allows for remote access for wafer processing. Thecontroller enables remote access to the system to monitor currentprogress of fabrication operations, examines a history of pastfabrication operations, examines trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process.

In some embodiments, a remote computer (e.g. a server) provides processrecipes to the system over a computer network, which includes a localnetwork or the Internet. The remote computer includes a user interfacethat enables entry or programming of parameters and/or settings, whichare then communicated to the system from the remote computer. In someexamples, the controller receives instructions in the form of settingsfor processing a wafer. It should be understood that the settings arespecific to a type of process to be performed on a wafer and a type oftool that the controller interfaces with or controls. Thus as describedabove, the controller is distributed, such as by including one or morediscrete controllers that are networked together and working towards acommon purpose, such as the fulfilling processes described herein. Anexample of a distributed controller for such purposes includes one ormore integrated circuits on a chamber in communication with one or moreintegrated circuits located remotely (such as at a platform level or aspart of a remote computer) that combine to control a process in achamber.

Without limitation, in various embodiments, the system includes a plasmaetch chamber, a deposition chamber, a spin-rinse chamber, a metalplating chamber, a clean chamber, a bevel edge etch chamber, a physicalvapor deposition (PVD) chamber, a chemical vapor deposition (CVD)chamber, an atomic layer deposition (ALD) chamber, an atomic layer etch(ALE) chamber, an ion implantation chamber, a track chamber, and anyother semiconductor processing chamber that is associated or used infabrication and/or manufacturing of semiconductor wafers.

It is further noted that although the above-described operations aredescribed with reference to a parallel plate plasma chamber, e.g., acapacitively coupled plasma chamber, etc., in some embodiments, theabove-described operations apply to other types of plasma chambers,e.g., a plasma chamber including an inductively coupled plasma (ICP)reactor, a transformer coupled plasma (TCP) reactor, conductor tools,dielectric tools, a plasma chamber including an electron cyclotronresonance (ECR) reactor, etc. For example, one or more RF generators arecoupled to an inductor within the ICP plasma chamber. Examples of ashape of the inductor include a solenoid, a dome-shaped coil, aflat-shaped coil, etc.

As noted above, depending on a process operation to be performed by thetool, the controller communicates with one or more of other toolcircuits or modules, other tool components, cluster tools, other toolinterfaces, adjacent tools, neighboring tools, tools located throughouta factory, a main computer, another controller, or tools used inmaterial transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

With the above embodiments in mind, it should be understood that some ofthe embodiments employ various computer-implemented operations involvingdata stored in computer systems. These computer-implemented operationsare those that manipulate physical quantities.

Some of the embodiments also relate to a hardware unit or an apparatusfor performing these operations. The apparatus is specially constructedfor a special purpose computer. When defined as a special purposecomputer, the computer performs other processing, program execution orroutines that are not part of the special purpose, while still beingcapable of operating for the special purpose.

In some embodiments, the operations, described herein, are performed bya computer selectively activated, or are configured by one or morecomputer programs stored in a computer memory, or are obtained over acomputer network. When data is obtained over the computer network, thedata may be processed by other computers on the computer network, e.g.,a cloud of computing resources.

One or more embodiments, described herein, can also be fabricated ascomputer-readable code on a non-transitory computer-readable medium. Thenon-transitory computer-readable medium is any data storage hardwareunit, e.g., a memory device, etc., that stores data, which is thereafterread by a computer system. Examples of the non-transitorycomputer-readable medium include hard drives, network attached storage(NAS), ROM, RAM, compact disc-ROMs (CD-ROMs), CD-recordables (CD-Rs),CD-rewritables (CD-RWs), magnetic tapes and other optical andnon-optical data storage hardware units. In some embodiments, thenon-transitory computer-readable medium includes a computer-readabletangible medium distributed over a network-coupled computer system sothat the computer-readable code is stored and executed in a distributedfashion.

Although some method operations, described above, were presented in aspecific order, it should be understood that in various embodiments,other housekeeping operations are performed in between the methodoperations, or the method operations are adjusted so that they occur atslightly different times, or are distributed in a system which allowsthe occurrence of the method operations at various intervals, or areperformed in a different order than that described above.

It should further be noted that in an embodiment, one or more featuresfrom any embodiment described above are combined with one or morefeatures of any other embodiment without departing from a scopedescribed in various embodiments described in the present disclosure.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, it will be apparent thatcertain changes and modifications can be practiced within the scope ofappended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the embodiments arenot to be limited to the details given herein, but may be modifiedwithin the scope and equivalents of the appended claims.

1. A method for achieving a pre-determined factor associated with an edge region within a plasma chamber, comprising: providing a radio frequency (RF) signal via a first impedance matching circuit to a main electrode within the plasma chamber, wherein the RF signal is generated based on a frequency of operation of a first RF generator; providing another RF signal via a second impedance matching circuit to an edge electrode within the plasma chamber, wherein the other RF signal is generated based on the frequency of operation of the first RF generator; receiving a first measurement of a variable associated with an output of the first impedance matching circuit; receiving a second measurement of the variable associated with an output of the second impedance matching circuit; modifying a phase of the other RF signal based on the first measurement and the second measurement; and changing a magnitude of a variable associated with a second RF generator to achieve the pre-determined factor.
 2. The method of claim 1, wherein changing the magnitude is performed after the other RF signal is generated and after the phase of the other RF signal is modified.
 3. The method of claim 1, wherein modifying the phase of the RF signal and the other RF signal comprises modifying the phase to achieve a phase of the first measurement that is within a pre-set range from a phase of the second measurement.
 4. The method of claim 1, wherein the variable associated with the second RF generator is different from the variable associated with the outputs of the first and second impedance matching circuits.
 5. The method of claim 1, wherein receiving the first measurement comprises receiving the first measurement from the output of the first impedance matching circuit, wherein receiving the second measurement comprises receiving the second measurement from the output of the second impedance matching circuit.
 6. The method of claim 1, wherein the main electrode is configured to support a substrate to process the substrate at a center region within the plasma chamber and the edge electrode is configured to process the substrate at the edge region.
 7. The method of claim 1, wherein the main electrode is a chuck, and the edge electrode is an edge ring or a coupling ring.
 8. The method of claim 1, wherein the main electrode is an upper electrode, and the edge electrode is an upper electrode extension.
 9. The method of claim 1, wherein the second RF generator is controlled to have a frequency of operation that is within a pre-determined range of the frequency of operation of the first RF generator.
 10. A system for achieving a pre-determined factor associated with an edge region, comprising: a plasma chamber having a main electrode and an edge electrode; a first impedance matching circuit coupled to the main electrode; a second impedance matching circuit coupled to the edge electrode; a first radio frequency (RF) generator coupled to the first impedance matching circuit to provide an RF signal via the first impedance matching circuit to the main electrode, wherein the RF signal is generated based on a frequency of operation of the first RF generator; a second RF generator coupled to the second impedance matching circuit to provide another RF signal via the second impedance matching circuit to the edge electrode, wherein the other RF signal is generated based on the frequency of operation of the first RF generator, wherein the second RF generator is configured to receive a first measurement of a variable associated with an output of the first impedance matching circuit, wherein the second RF generator is configured to receive a second measurement of the variable associated with an output of the second impedance matching circuit, wherein the second RF generator is configured to modify a phase of the other RF signal based on the first measurement and the second measurement, and wherein the second RF generator is configured to change a magnitude of a variable associated with the second RF generator to achieve the pre-determined factor.
 11. The system of claim 10, wherein the magnitude is changed after the other RF signal is generated and after the phase of the other RF signal is modified.
 12. The system of claim 10, wherein the first measurement is received from the output of the first impedance matching circuit, wherein the second measurement is received from the output of the second impedance matching circuit.
 13. The system of claim 10, wherein the second RF generator is configured to modify the phase of the other RF signal to achieve a phase of the first measurement that is within a pre-set range from a phase of the second measurement.
 14. The system of claim 10, wherein the variable associated with the second RF generator is different from the variable associated with the outputs of the first and second impedance matching circuits.
 15. The system of claim 10, wherein the second RF generator is controlled to have a frequency of operation that is within a pre-determined range of the frequency of operation of the first RF generator.
 16. The system of claim 10, wherein the main electrode is configured to support a substrate to process the substrate at a center region within the plasma chamber and the edge electrode is configured to process the substrate at the edge region.
 17. The system of claim 10, wherein the main electrode is a chuck, and the edge electrode is an edge ring or a coupling ring.
 18. The system of claim 10, wherein the main electrode is an upper electrode, and the edge electrode is an upper electrode extension.
 19. A non-transitory computer readable medium containing program instructions for achieving a pre-determined factor associated with an edge region within a plasma chamber, wherein execution of the program instructions by one or more processors of a computer system causes the one or more processors to carry out operations of: providing a radio frequency (RF) signal via a first impedance matching circuit to a main electrode within the plasma chamber, wherein the RF signal is generated based on a frequency of operation of a first RF generator; providing another RF signal via a second impedance matching circuit to an edge electrode within the plasma chamber, wherein the other RF signal is generated based on the frequency of operation of the first RF generator; receiving a first measurement of a variable associated with an output of the first impedance matching circuit; receiving a second measurement of the variable associated with an output of the second impedance matching circuit; modifying a phase of the other RF signal based on the first measurement and the second measurement; and changing a magnitude of a variable associated with a second RF generator to achieve the pre-determined factor.
 20. The non-transitory computer readable medium of claim 19, wherein changing the magnitude is performed after the other RF signal is generated and after the phase of the other RF signal is modified. 